#include <bits/stdc++.h>
using namespace std;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
using ll = long long;
using P = pair<ll, ll>;
const long double PI = acos(-1.0L);
ll GCD(ll a, ll b) { return b?GCD(b, a%b):a; }
ll LCM(ll a, ll b) { return a/GCD(a, b)*b; }

int n;
long double dp[1000100][10];

int main() {
    cin >> n;
    for(int i = 0; i <= n; ++i) {
        for(int j = 0; j <= 6; ++j) dp[i][j] = 0LL;
    }
    dp[0][0] = 1LL;
    for(int i = 0; i < n; ++i) {
        for(int j = 0; j < 6; ++j) {
            int add = 6-j; int stay = j+1;
            // dp[i+1][j] = (dp[i][j]*(long double)stay/(long double)6);
            dp[i+1][j+1] = ((dp[i][j]*(long double)add/(long double)6) + (dp[i][j+1]*(long double)stay/(long double)6));
        }
    }

    /*for(int i = 0; i <= n; ++i) {
        for(int j = 0; j <= 6; ++j) {
            cout << setprecision(14) << dp[i][j] << " ";
        }
        cout << endl;
    }*/

    cout << setprecision(14) << dp[n][6] << endl;
}