#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#include <cmath>using namespace std;#define sqr(x) ((x) * (x))const int MAXN = 55;const double EPS = 1e-8;const double PI = acos(-1.0);//3.14159265358979323846const double INF = 1;const double eps = 1e-8;int sgn(double x){    if(x > eps)    return 1;    else if(x < - eps)  return -1;    else    return 0;}struct POINT {    double x, y, ag;    POINT() {}    POINT(double x, double y): x(x), y(y) {}    void read() {        scanf("%lf%lf", &x, &y);    }    bool operator == (const POINT &rhs) const {        return sgn(x - rhs.x) == 0 && sgn(y - rhs.y) == 0;    }    bool operator < (const POINT &rhs) const {        if(y != rhs.y) return y < rhs.y;        return x < rhs.x;    }    POINT operator + (const POINT &rhs) const {        return POINT(x + rhs.x, y + rhs.y);    }    POINT operator - (const POINT &rhs) const {        return POINT(x - rhs.x, y - rhs.y);    }    POINT operator * (const double &b) const {        return POINT(x * b, y * b);    }    POINT operator / (const double &b) const {        return POINT(x / b, y / b);    }    double operator * (const POINT &rhs) const {        return x * rhs.x + y * rhs.y;    }    double length() {        return sqrt(x * x + y * y);    }    double angle() {        return atan2(y, x);    }    POINT unit() {        return *this / length();    }    void makeAg() {        ag = atan2(y, x);    }    void print() {        printf("%.10f %.10f\n", x, y);    }};typedef POINT Vector;double dist(const POINT &a, const POINT &b) {    return (a - b).length();}double cross(const POINT &a, const POINT &b) {    return a.x * b.y - a.y * b.x;}//ret >= 0 means turn rightdouble cross(const POINT &sp, const POINT &ed, const POINT &op) {    return cross(sp - op, ed - op);}double area(const POINT& a, const POINT &b, const POINT &c) {    return fabs(cross(a - c, b - c)) / 2;}//counter-clockwisePOINT rotate(const POINT &p, double angle, const POINT &o = POINT(0, 0)) {    POINT t = p - o;    double x = t.x * cos(angle) - t.y * sin(angle);    double y = t.y * cos(angle) + t.x * sin(angle);    return POINT(x, y) + o;}double cosIncludeAngle(const POINT &a, const POINT &b, const POINT &o) {    POINT p1 = a - o, p2 = b - o;    return (p1 * p2) / (p1.length() * p2.length());}double includedAngle(const POINT &a, const POINT &b, const POINT &o) {    return acos(cosIncludeAngle(a, b, o));    /*    double ret = abs((a - o).angle() - (b - o).angle());    if(sgn(ret - PI) > 0) ret = 2 * PI - ret;    return ret;    */}struct SEG {    POINT st, ed;    double ag;    SEG() {}    SEG(POINT st, POINT ed): st(st), ed(ed) {}    void read() {        st.read(); ed.read();    }    void makeAg() {        ag = atan2(ed.y - st.y, ed.x - st.x);    }};typedef SEG Line;//ax + by + c > 0Line buildLine(double a, double b, double c) {    if(sgn(a) == 0 && sgn(b) == 0) return Line(POINT(sgn(c) > 0 ? -1 : 1, INF), POINT(0, INF));    if(sgn(a) == 0) return Line(POINT(sgn(b), -c/b), POINT(0, -c/b));    if(sgn(b) == 0) return Line(POINT(-c/a, 0), POINT(-c/a, sgn(a)));    if(b < 0) return Line(POINT(0, -c/b), POINT(1, -(a + c) / b));    else return Line(POINT(1, -(a + c) / b), POINT(0, -c/b));}void moveRight(Line &v, double r) {    double dx = v.ed.x - v.st.x, dy = v.ed.y - v.st.y;    dx = dx / dist(v.st, v.ed) * r;    dy = dy / dist(v.st, v.ed) * r;    v.st.x += dy; v.ed.x += dy;    v.st.y -= dx; v.ed.y -= dx;}bool isOnSEG(const SEG &s, const POINT &p) {    return (p == s.st || p == s.ed) ||        (((p.x - s.st.x) * (p.x - s.ed.x) < 0 ||          (p.y - s.st.y) * (p.y - s.ed.y) < 0) &&         sgn(cross(s.ed, p, s.st)) == 0);}bool isInSEGRec(const SEG &s, const POINT &p) {    return sgn(min(s.st.x, s.ed.x) - p.x) <= 0 && sgn(p.x - max(s.st.x, s.ed.x)) <= 0        && sgn(min(s.st.y, s.ed.y) - p.y) <= 0 && sgn(p.y - max(s.st.y, s.ed.y)) <= 0;}bool isIntersected(const POINT &s1, const POINT &e1, const POINT &s2, const POINT &e2) {    return (max(s1.x, e1.x) >= min(s2.x, e2.x)) &&        (max(s2.x, e2.x) >= min(s1.x, e1.x)) &&        (max(s1.y, e1.y) >= min(s2.y, e2.y)) &&        (max(s2.y, e2.y) >= min(s1.y, e1.y)) &&        (cross(s2, e1, s1) * cross(e1, e2, s1) >= 0) &&        (cross(s1, e2, s2) * cross(e2, e1, s2) >= 0);}bool isIntersected(const SEG &a, const SEG &b) {    return isIntersected(a.st, a.ed, b.st, b.ed);}bool isParallel(const SEG &a, const SEG &b) {    return sgn(cross(a.ed - a.st, b.ed - b.st)) == 0;}//return Ax + By + C =0 ‘s A, B, Cvoid Coefficient(const Line &L, double &A, double &B, double &C) {    A = L.ed.y - L.st.y;    B = L.st.x - L.ed.x;    C = L.ed.x * L.st.y - L.st.x * L.ed.y;}//POINT of intersectionPOINT operator * (const Line &a, const Line &b) {    double A1, B1, C1;    double A2, B2, C2;    Coefficient(a, A1, B1, C1);    Coefficient(b, A2, B2, C2);    POINT I;    I.x = - (B2 * C1 - B1 * C2) / (A1 * B2 - A2 * B1);    I.y =   (A2 * C1 - A1 * C2) / (A1 * B2 - A2 * B1);    return I;}bool isEqual(const Line &a, const Line &b) {    double A1, B1, C1;    double A2, B2, C2;    Coefficient(a, A1, B1, C1);    Coefficient(b, A2, B2, C2);    return sgn(A1 * B2 - A2 * B1) == 0 && sgn(A1 * C2 - A2 * C1) == 0 && sgn(B1 * C2 - B2 * C1) == 0;}double POINT_to_Line(const POINT &p, const Line &L) {    return fabs(cross(p, L.st, L.ed)/dist(L.st, L.ed));}double POINT_to_SEG(const POINT &p, const SEG &L) {    if(sgn((L.ed - L.st) * (p - L.st)) < 0) return dist(p, L.st);    if(sgn((L.st - L.ed) * (p - L.ed)) < 0) return dist(p, L.ed);    return POINT_to_Line(p, L);}double SEG_to_SEG(const SEG &a, const SEG &b) {    double ans1 = min(POINT_to_SEG(a.st, b), POINT_to_SEG(a.ed, b));    double ans2 = min(POINT_to_SEG(b.st, a), POINT_to_SEG(b.ed, a));    return min(ans1, ans2);}struct Circle {    POINT c;    double r;    Circle() {}    Circle(POINT c, double r): c(c), r(r) {}    void read() {        c.read();        scanf("%lf", &r);    }    double area() const {        return PI * r * r;    }    bool contain(const Circle &rhs) const {        return sgn(dist(c, rhs.c) + rhs.r - r) <= 0;    }    bool contain(const POINT &p) const {        return sgn(dist(c, p) - r) <= 0;    }    bool intersect(const Circle &rhs) const {        return sgn(dist(c, rhs.c) - r - rhs.r) < 0;    }    bool tangency(const Circle &rhs) const {        return sgn(dist(c, rhs.c) - r - rhs.r) == 0;    }    POINT pos(double angle) const {        POINT p = POINT(c.x + r, c.y);        return rotate(p, angle, c);    }};double CommonArea(const Circle &A, const Circle &B) {    double area = 0.0;    const Circle & M = (A.r > B.r) ? A : B;    const Circle & N = (A.r > B.r) ? B : A;    double D = dist(M.c, N.c);    if((D < M.r + N.r) && (D > M.r - N.r)) {        double cosM = (M.r * M.r + D * D - N.r * N.r) / (2.0 * M.r * D);        double cosN = (N.r * N.r + D * D - M.r * M.r) / (2.0 * N.r * D);        double alpha = 2 * acos(cosM);        double beta = 2 * acos(cosN);        double TM = 0.5 * M.r * M.r * (alpha - sin(alpha));        double TN = 0.5 * N.r * N.r * (beta - sin(beta));        area = TM + TN;    }    else if(D <= M.r - N.r) {        area = N.area();    }    return area;}int intersection(const SEG &s, const Circle &cir, POINT &p1, POINT &p2) {    double angle = cosIncludeAngle(s.ed, cir.c, s.st);    //double angle1 = cos(includedAngle(s.ed, cir.c, s.st));    double B = dist(cir.c, s.st);    double a = 1, b = -2 * B * angle, c = sqr(B) - sqr(cir.r);    double delta = sqr(b) - 4 * a * c;    if(sgn(delta) < 0) return 0;    if(sgn(delta) == 0) delta = 0;    double x1 = (-b - sqrt(delta)) / (2 * a), x2 = (-b + sqrt(delta)) / (2 * a);    Vector v = (s.ed - s.st).unit();    p1 = s.st + v * x1;    p2 = s.st + v * x2;    return 1 + sgn(delta);}double CommonArea(const Circle &cir, POINT p1, POINT p2) {    if(p1 == cir.c || p2 == cir.c) return 0;    if(cir.contain(p1) && cir.contain(p2)) {        return area(cir.c, p1, p2);    } else if(!cir.contain(p1) && !cir.contain(p2)) {        POINT q1, q2;        int t = intersection(Line(p1, p2), cir, q1, q2);        if(t == 0) {            double angle = includedAngle(p1, p2, cir.c);            return 0.5 * sqr(cir.r) * angle;        } else {            double angle1 = includedAngle(p1, p2, cir.c);            double angle2 = includedAngle(q1, q2, cir.c);            if(isInSEGRec(SEG(p1, p2), q1))return 0.5 * sqr(cir.r) * (angle1 - angle2 + sin(angle2));            else return 0.5 * sqr(cir.r) * angle1;        }    } else {        if(cir.contain(p2)) swap(p1, p2);        POINT q1, q2;        intersection(Line(p1, p2), cir, q1, q2);        double angle = includedAngle(q2, p2, cir.c);        double a = area(cir.c, p1, q2);        double b = 0.5 * sqr(cir.r) * angle;        return a + b;    }}struct Triangle {    POINT p[3];    Triangle() {}    Triangle(POINT *t) {        for(int i = 0; i < 3; ++i) p[i] = t[i];    }    void read() {        for(int i = 0; i < 3; ++i) p[i].read();    }    double area() const {        return ::area(p[0], p[1], p[2]);    }    POINT& operator[] (int i) {        return p[i];    }};double CommonArea(Triangle tir, const Circle &cir) {    double ret = 0;    ret += sgn(cross(tir[0], cir.c, tir[1])) * CommonArea(cir, tir[0], tir[1]);    ret += sgn(cross(tir[1], cir.c, tir[2])) * CommonArea(cir, tir[1], tir[2]);    ret += sgn(cross(tir[2], cir.c, tir[0])) * CommonArea(cir, tir[2], tir[0]);    return abs(ret);}struct POLY {    int n;    POINT p[MAXN];//p[n] = p[0]    void init(POINT *pp, int nn) {        n = nn;        for(int i = 0; i < n; ++i) p[i] = pp[i];        p[n] = p[0];    }    double area() {        if(n < 3) return 0;        double s = p[0].y * (p[n - 1].x - p[1].x);        for(int i = 1; i < n; ++i)            s += p[i].y * (p[i - 1].x - p[i + 1].x);        return s / 2;    }};//the convex hull is clockwisevoid Graham_scan(POINT *p, int n, int *stk, int &top) {//stk[0] = stk[top]    sort(p, p + n);    top = 1;    stk[0] = 0; stk[1] = 1;    for(int i = 2; i < n; ++i) {        while(top && cross(p[i], p[stk[top]], p[stk[top - 1]]) <= 0) --top;        stk[++top] = i;    }    int len = top;    stk[++top] = n - 2;    for(int i = n - 3; i >= 0; --i) {        while(top != len && cross(p[i], p[stk[top]], p[stk[top - 1]]) <= 0) --top;        stk[++top] = i;    }}//use for half_planes_crossbool cmpAg(const Line &a, const Line &b) {    if(sgn(a.ag - b.ag) == 0)        return sgn(cross(b.ed, a.st, b.st)) < 0;    return a.ag < b.ag;}//clockwise, plane is on the rightbool half_planes_cross(Line *v, int vn, POLY &res, Line *deq) {    int i, n;    sort(v, v + vn, cmpAg);    for(i = n = 1; i < vn; ++i) {        if(sgn(v[i].ag - v[i-1].ag) == 0) continue;        v[n++] = v[i];    }    int head = 0, tail = 1;    deq[0] = v[0], deq[1] = v[1];    for(i = 2; i < n; ++i) {        if(isParallel(deq[tail - 1], deq[tail]) || isParallel(deq[head], deq[head + 1]))            return false;        while(head < tail && sgn(cross(v[i].ed, deq[tail - 1] * deq[tail], v[i].st)) > 0)            --tail;        while(head < tail && sgn(cross(v[i].ed, deq[head] * deq[head + 1], v[i].st)) > 0)            ++head;        deq[++tail] = v[i];    }    while(head < tail && sgn(cross(deq[head].ed, deq[tail - 1] * deq[tail], deq[head].st)) > 0)        --tail;    while(head < tail && sgn(cross(deq[tail].ed, deq[head] * deq[head + 1], deq[tail].st)) > 0)        ++head;    if(tail <= head + 1) return false;    res.n = 0;    for(i = head; i < tail; ++i)        res.p[res.n++] = deq[i] * deq[i + 1];    res.p[res.n++] = deq[head] * deq[tail];    res.n = unique(res.p, res.p + res.n) - res.p;    res.p[res.n] = res.p[0];    return true;}//ix and jx is the POINTs whose distance is return, res.p[n - 1] = res.p[0], res must be clockwisedouble dia_rotating_calipers(POLY &res, int &ix, int &jx) {    double dia = 0;    int q = 1;    for(int i = 0; i < res.n - 1; ++i) {        while(sgn(cross(res.p[i], res.p[q + 1], res.p[i + 1]) - cross(res.p[i], res.p[q], res.p[i + 1])) > 0)            q = (q + 1) % (res.n - 1);        if(sgn(dist(res.p[i], res.p[q]) - dia) > 0) {            dia = dist(res.p[i], res.p[q]);            ix = i; jx = q;        }        if(sgn(dist(res.p[i + 1], res.p[q]) - dia) > 0) {            dia = dist(res.p[i + 1], res.p[q]);            ix = i + 1; jx = q;        }    }    return dia;}//a and b must be clockwise, find the minimum distance between two convex hulldouble half_rotating_calipers(POLY &a, POLY &b) {    int sa = 0, sb = 0;    for(int i = 0; i < a.n; ++i) if(sgn(a.p[i].y - a.p[sa].y) < 0) sa = i;    for(int i = 0; i < b.n; ++i) if(sgn(b.p[i].y - b.p[sb].y) < 0) sb = i;    double tmp, ans = dist(a.p[0], b.p[0]);    for(int i = 0; i < a.n; ++i) {        while(sgn(tmp = cross(a.p[sa], a.p[sa + 1], b.p[sb + 1]) - cross(a.p[sa], a.p[sa + 1], b.p[sb])) > 0)            sb = (sb + 1) % (b.n - 1);        if(sgn(tmp) < 0) ans = min(ans, POINT_to_SEG(b.p[sb], SEG(a.p[sa], a.p[sa + 1])));        else ans = min(ans, SEG_to_SEG(SEG(a.p[sa], a.p[sa + 1]), SEG(b.p[sb], b.p[sb + 1])));        sa = (sa + 1) % (a.n - 1);    }    return ans;}double rotating_calipers(POLY &a, POLY &b) {    return min(half_rotating_calipers(a, b), half_rotating_calipers(b, a));}/*******************************************************************************************/POINT p[MAXN];Circle cir1, cir2, cir3;int main(){    double x1, y1, R, r, x2, y2, k;    scanf("%lf%lf%lf%lf%lf%lf%lf",&x1,&y1,&R,&r,&x2,&y2,&k);    cir1 = Circle(POINT(x1, y1), R);    cir2 = Circle(POINT(x1, y1), r);    cir3 = Circle(POINT(x2, y2), k);    printf("%.2f\n",CommonArea(cir3, cir1) - CommonArea(cir3, cir2));}