#include <cmath>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <functional>
#include <queue>
#include <iostream>
#include <string.h>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <cstdint>
#include <climits>
#include <unordered_set>
#include <sstream>
#include <stack>

using namespace std;

typedef long long int ll;
typedef pair<ll,ll> pii;
typedef tuple<double,int,int> t3;

using namespace std;

int n;
double dp[(int)1e7][7];

void solve()
{
    cin >> n;
    dp[1][1] = 1;
    for(int t = 2;t <= n;t++)
    {
        for(int i = 1;i <= 6;i++)
        {
            dp[t][i] += dp[t-1][i] * i/6.0;
            dp[t][i+1] += dp[t-1][i] * (6-i)/6.0;
        }
    }
    cout << fixed << setprecision(10);
    cout << dp[n][6] << endl;
}

int main()
{
    solve();
    return 0;
}