#include <iostream>
#include <iomanip>
#include <cmath>

long long factorial(long long a) {
    long long r = 1;
    for (; a > 0; a--) {
        r *= a;
    }
    return r;
}

long long combination(long long a, long long b) {
    return factorial(a) / (factorial(a - b) * factorial(b));
}

int main() {
    using namespace std;
    long long n;
    double p = 0.;
    cin >> n;
    if (n < 6) {
        p = 0;
    } else {
        for (int i = 1; i <= 6; i++) {
            double s = (i % 2) ? -1 : 1;
            p += combination(6, i) * pow(i / 6., (double)n) * s;
        }
    }
    cout << fixed << setprecision(10) << p << endl;
}