#include <bits/stdc++.h>

using namespace std;

double dp[7];

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n;
	cin >> n;
	dp[0] = 1;
	for (int i = 0; i < n; i++) {
		for (int j = 5; j >= 0; j--) {
			dp[j + 1] += dp[j] * (6 - j) / 6;
			dp[j] = dp[j] * j / 6;
		}
	}

	cout << fixed << setprecision(10) << dp[6] << endl;
	return 0;
}