#include <iostream>
#include <iomanip>
#include <vector>
using namespace std;
int main(){
	cout << fixed << setprecision(20);
	int n;
	cin >> n;
	vector<vector<double>> dp(n + 1, vector<double>(7, 0));
	dp[0][0] = 1;
	for (int i = 0; i < n; i++){
		for (int j = 0; j <= 6; j++){
			double p = (double) j / 6;
			dp[i + 1][j] += dp[i][j] * p;
			if (j < 6){
				dp[i + 1][j + 1] += dp[i][j] * (1 - p);
			}
		}
	}
	cout << dp[n][6] << endl;
}