#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int main() {
    int n;
    cin>>n;
    double dp[n+1][7]{};
    dp[0][0]=1;
    for (int i=1;i<=n;i++)
        for (int j=1;j<=6;j++)
            dp[i][j]=dp[i-1][j-1]*(6-j+1)/6.0+dp[i-1][j]*j/6.0;
    cout<<fixed<<setprecision(7)<<dp[n][6]<<endl;
    return 0;
}