#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <cmath>using namespace std;typedef long long ll;const int N=1005,INF=1e9;const double eps=1e-13;inline int sgn(double x){    if(abs(x)<eps) return 0;    else return x<0?-1:1;}inline int read(){    char c=getchar();int x=0,f=1;    while(c<‘0‘||c>‘9‘){if(c==‘-‘)f=-1; c=getchar();}    while(c>=‘0‘&&c<=‘9‘){x=x*10+c-‘0‘; c=getchar();}    return x*f;}int n;struct Interval{    double l,r;    bool operator <(const Interval &a) const{        return l==a.l?r<a.r:l<a.l;    }    Interval(double a=0,double b=0):l(a),r(b){}}a[N],b[N];struct Circle{    int x,y,r;    Circle(){}    Circle(int x,int y,int r):x(x),y(y),r(r){}    Interval f(double p){        double dx=x-p,t=sqrt(r*r-dx*dx);        return Interval(y-t,y+t);    }}C[N];double Dis(Circle a,Circle b){    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));}bool del[N];void iniCircle(){    for(int i=1;i<=n;i++) if(!del[i])        for(int j=i+1;j<=n;j++) if(!del[j])            if(Dis(C[i],C[j])<=abs(C[i].r-C[j].r)){                if(C[i].r>C[j].r) del[j]=1;                else del[i]=1;            }    int p=0;    for(int i=1;i<=n;i++) if(!del[i]) C[++p]=C[i];    n=p;}inline double F(double x){    int m=0;    for(int i=1;i<=n;i++)        if(C[i].x-C[i].r<=x&&x<=C[i].x+C[i].r) a[++m]=C[i].f(x);    sort(a+1,a+1+m);    double last=-INF,re=0;    for(int i=1;i<=m;i++){        if(a[i].l>last) re+=a[i].r-a[i].l,last=a[i].r;        else if(a[i].r>last) re+=a[i].r-last,last=a[i].r;    }    return re;}inline double cal(double l,double r){    return (F(l)+F(r)+4*F((l+r)/2))*(r-l)/6;}inline double cal(double l,double r,double fl,double fr,double fm){    return (fl+fr+4*fm)*(r-l)/6;}double Simpson(double l,double r,double now,double fl,double fr,double fm){    double mid=(l+r)/2,flm=F((l+mid)/2),frm=F((mid+r)/2);    double p=cal(l,mid,fl,fm,flm),q=cal(mid,r,fm,fr,frm);    if(sgn(now-p-q)==0) return now;    else return Simpson(l,mid,p,fl,fm,flm)+Simpson(mid,r,q,fm,fr,frm);}double lb=INF,rb=-INF;int main(int argc, const char * argv[]) {    n=read();    for(int i=1;i<=n;i++){//printf("i %d\n",i);        C[i].x=read();C[i].y=read();C[i].r=read();        lb=min(lb,(double)C[i].x-C[i].r);        rb=max(rb,(double)C[i].x+C[i].r);    }    iniCircle();    //printf("%d\n",n);    double fl=F(lb),fr=F(rb),fm=F((lb+rb)/2);    printf("%.3lf",Simpson(lb,rb,cal(lb,rb,fl,fr,fm),fl,fr,fm));    return 0;}