#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define REP(i, n) rep(i, 0, n)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define int long long
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
using namespace std;
typedef pair<int, int> P;
const int mod = 1000000007;
const int INF = 1e12;
 
double c[51][51];
void f(){
    rep(i, 0, 51) c[i][0] = 1;
    rep(i, 1, 51){
        rep(j, 1, 51){
            c[i][j] = c[i - 1][j - 1] + c[i - 1][j];
        }
    }
}

signed main(){
    // ios::sync_with_stdio(false);
    // cin.tie(0);
    int n;
    cin >> n;
    f();
    double ans = 0.0;
    if(n >= 6){
        int k = -1;
        rep(i, 1, 7){
            ans += (double)k * c[6][i] * pow((double)i / (double)6, n);
            k *= -1;
        }
    }
    printf("%.15lf\n", ans);
}