#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

double my_pow(double x, ll n) {
    if (n == 0) return 1;
    if (n % 2 == 0) return my_pow(x * x, n / 2);
    return x * my_pow(x, n - 1);
}


int main() {
    int N;
    cin >> N;
    double s = 1;
    for (int i = 2; i < 10; i++) {
        s += my_pow((double)1 / i, N);
    }
    printf("%.9f\n", s);
    return 0;
}