#include <bits/stdc++.h>
using namespace std;
using ld = long double;

int main()
{
	vector<ld> dp(7);
	dp[0] = 1;
	int N;
	cin >> N;
	for (int i = 0; i < N; i++) {
		auto t = dp;
		fill(dp.begin(), dp.end(), (ld)0);
		for (int j = 0; j <= 6; j++) {
			dp[j] += t[j] * ((ld)j / 6);
			if (j != 6) dp[j + 1] += t[j] * ((ld)(6 - j) / 6);
		}
	}
	cout << fixed << setprecision(9) << dp[6] << endl;
	return 0;
}