UVa 1388 - Graveyard

#include <cstdio>
#include <cmath>
using namespace std;

int main()
{
#ifdef LOCAL
freopen("in", "r", stdin);
#endif
int n, m;
while(scanf("%d%d", &n, &m) != EOF)
{
double ans = 0;
for(int i = 1; i < n; i++)
{
double pos = double(i) * (n+m) / n;
ans += fabs(pos - floor(pos+0.5)) / (n+m);
}
printf("%.4lf\n", ans*10000);
}
return 0;
}