#include <iostream>#include <algorithm>#include <cstdio>#include <cstring>#include <vector>using namespace std;double p[1086][1086];int x,y;double dp(int i,int j){    if(p[i][j]>=0)        return p[i][j];    if(i>x||j>y)        return 0;    if(i==x&&j==y)        return 0;    double xx=0.0;    xx+=dp(i+1,j)*(x-i)*j/x/y;    xx+=dp(i,j+1)*(y-j)*i/x/y;    xx+=1.0;    xx+=dp(i+1,j+1)*(y-j)*(x-i)/x/y;    xx/=(1-(double)i*j/x/y);    return p[i][j]=xx;}int main(){    while(scanf("%d%d",&x,&y)!=EOF)    {        for(int i=0;i<x+2;i++)            for(int j=0;j<y+3;j++)                p[i][j]=-1.0;        p[x][y]=0;        printf("%.9f\n",dp(0,0));    }    return 0;}

#include <iostream>#include <algorithm>#include <cstdio>#include <cstring>#include <cmath>#define eps 1e-5using namespace std;double p[1086][1086];int x,y;double stay[1086][1086],xia[1086][1086],you[1085][1086];bool vis[1086][1086];double dp(int i,int j){    if(i>=x||j>=y)        return 0;    if(vis[i][j])        return p[i][j];    vis[i][j]=true;    p[i][j]=xia[i][j]*dp(i,j+1)+you[i][j]*dp(i+1,j)+2;    if(fabs(1-stay[i][j])<eps)        return p[i][j]=0;    else        return p[i][j]=(p[i][j]/(1-stay[i][j]));}int main(){    while(scanf("%d%d",&x,&y)!=EOF)    {        memset(vis,false,sizeof vis);        memset(p,0,sizeof p);        for(int i=0;i<x;i++)        {            for(int j=0;j<y;j++)            {                scanf("%lf%lf%lf",&stay[i][j],&xia[i][j],&you[i][j]);            }        }        vis[x-1][y-1]=true;        p[x-1][y-1]=0.0;        printf("%.3lf\n",dp(0,0));    }    return 0;}

#pragma comment(linker, "/STACK:102400000,102400000")#include <iostream>#include <algorithm>#include <cstdio>#include <cstring>#include <cmath>#define eps 1e-5using namespace std;double p[100086];bool vis[100086];int next[100086],n,m;double dp(int x){    if(vis[x])        return p[x];    if(x>=n)        return 0;    double ret=0.0;    for(int i=1;i<7;i++)    {        int y=x+i;        while(next[y]!=-1)            y=next[y];        ret+=dp(y);    }    ret=ret/6+1;    vis[x]=1;    return p[x]=ret;}int main(){    while(scanf("%d%d",&n,&m),m+n)    {        memset(vis,false,sizeof vis);        memset(next,-1,sizeof next);        int a,b;        for(int i=0;i<m;i++)            scanf("%d%d",&a,&b),next[a]=b;        printf("%.4f\n",dp(0));    }    return 0;}

#include <iostream>#include <algorithm>#include <cstdio>#include <cstring>#include <cmath>#define eps 1e-5using namespace std;double ap[1086],bp[1086],p[186];int main(){    int T;    cin>>T;    while(T--)    {        int n,k1,k2,k3,kkk,a,b,c;        scanf("%d%d%d%d%d%d%d",&n,&k1,&k2,&k3,&a,&b,&c);        memset(p,0,sizeof p);        kkk=k1+k2+k3;        double pp;        for(int i=1;i<=k1;i++)        {            for(int j=1;j<=k2;j++)            {                for(int k=1;k<=k3;k++)                {                    if(i==a&&j==b&&k==c)                        pp=1.0/k1/k2/k3;                    else                        p[i+j+k]+=1.0/k1/k2/k3;                }            }        }        memset(ap,0,sizeof ap);        memset(bp,0,sizeof bp);        for(int i=n;i>=0;i--)        {            for(int j=1;j<=kkk;j++)            {                ap[i]+=ap[i+j]*p[j];                bp[i]+=bp[i+j]*p[j];            }            ap[i]+=pp;            bp[i]+=1;        }        printf("%.10f\n",bp[0]/(1.0-ap[0]));    }    return 0;}