#include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;

const int INF = (1 << 30) - 1;
const ll INF64 = ((ll)1 << 62) - 1;
const double PI = 3.1415926535897932384626433832795;

const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { -1, 0, 1, 0 };

int main() {
	//ios::sync_with_stdio(false);
	//cin.tie(0);

	int n;
	cin >> n;

	vector<vector<double>> dp(n + 1, vector<double>(8));
	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;
		}
	}

	printf("%.15lf\n", dp[n][6]);
	return 0;
}