#include <iostream>
#include <iomanip>
using namespace std;

int main(){
	int n;
	cin >> n;
	double dp[n + 1][6 + 1]{};
	dp[0][0] = 1;
	for(int i = 0; i < n; i++) for(int j = 0; j <= 6; j++){
		dp[i + 1][j + 1] += dp[i][j] * (6 - j) / 6;
		dp[i + 1][j] += dp[i][j] * j / 6;
	}
	cout << fixed << setprecision(10) << dp[n][6] << endl;
}