UVa1388 - Graveyard

#include<bits/stdc++.h>
using namespace std;
int main()
{
int n,m;
while(scanf("%d%d",&n,&m)==2)
{
double ans=0.0;
for(int i=1;i<n;i++){
double pos = (double) i / n * (n+m);
ans += fabs(pos - floor(pos + 0.5)) / (n+m);
}
printf("%.4lf\n",ans*10000);
}
return 0;
}