#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream>
#include <random>
#include<map>
#include <iomanip>
#include <time.h>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
#include <cassert>
#include<fstream>
#include <unordered_map>
#include <cstdlib>
using namespace std;
#define Ma_PI 3.141592653589793
#define eps 0.00000000000000000000000001
#define LONG_INF 10000000000000000
#define GOLD 1.61803398874989484820458
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
double dp[7] = {};
int main() {
	int n;
	cin >> n;
	dp[0] = 1.0;
	for (int i = 0;i < n;++i) {
		for (int q = 5;q >= 0;--q) {
			double hoge = 6-q;
			hoge /= 6.0;
			dp[q + 1] += dp[q] * hoge;
			hoge = q;
			hoge /= 6.0;
			dp[q] = dp[q] * hoge;
		}
	}
	cout <<fixed << setprecision(12) << dp[6] << endl;
	return 0;
}