#include <iostream>
#include <fstream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <cstring>
#include <string>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <algorithm>
using namespace std;

#define REP(i,n) for(int i=0; i<n; ++i)
#define FOR(i,a,b) for(int i=a; i<=b; ++i)
#define FORR(i,a,b) for (int i=a; i>=b; --i)
#define ALL(c) (c).begin(), (c).end()

typedef long long ll;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector<VI> VVI;
typedef vector<VL> VVL;
typedef pair<int,int> P;
typedef pair<ll,ll> PL;

double dp[1000001][7];

int main(){
    int n;
    cin >> n;

    dp[0][0] = 1.0;
    REP(i,n) FOR(j,0,6){
        dp[i+1][j+1] += (6.0 - j) / 6.0 * dp[i][j];
        dp[i+1][j] += j / 6.0 * dp[i][j];
    }
    printf("%.10f\n", dp[n][6]);

    // FOR(i,1,n){
    //     FOR(j,1,6) cout << dp[i][j] << " ";
    //     cout << endl;
    // }

    return 0;
}