Zar2

#include <iostream>
#include <iomanip>
using namespace std;
float dp[101][601];
int main()
{
    int n,a,b;
    cin>>n>>a>>b;
    for(int j=1;j<=6;++j)
        dp[1][j]=1/6.0;
    float s;
    for(int i=2;i<=n;++i)
        for(int j=1;j<=6*n;++j)
        {
            s=0.0;
            int Min=min(j-1,6);
            for(int k=1;k<=Min;++k)
                s+=dp[i-1][j-k],
            dp[i][j]=s/6.0;
        }
    s=0.0;
    for(int j=a;j<=b;++j)
        s+=dp[n][j];
    cout<<fixed<<setprecision(6)<<s<<'\n';
    return 0;
}