#include <iostream>
#include <vector>
#include <iomanip>

using namespace std;

int main(){
    int N; cin >> N;

    vector<vector<double> > dp(N+1,vector<double>(7,0.0));
    // dp[i][j] i回投げて，j種類の面が出ている確率
    dp[0][0] = 1.0;

    for(int i=0;i<N;i++){
        for(int j=0;j<=6;j++){
            dp[i+1][j+1] += dp[i][j] * (double)(6-j)/6.0;
            dp[i+1][j] += dp[i][j] * (double)j/6.0;
        }
    }
    cout << fixed << setprecision(15);
    cout << dp[N][6] << endl;
    return 0;
}