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

int main(){
    int n;
    cin >> n;
    vector<vector<double>> dp(n + 1, vector<double>(1 << 6));
    dp[0][0] = 1;
    for(int i = 0; i < n; i++){
        for(int j = 0; j < (1 << 6); j++){
            for(int k = 0; k < 6; k++){
                dp[i + 1][j | (1 << k)] += dp[i][j] / 6;
            }
        }
    }
    printf("%.15lf\n", dp[n].back());
}