#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main(){
    int n; cin >> n;
    if(n >= 25){
        cout << 1 << endl;
        return 0;
    }
    long double ans = 0;
    int i = 1;
    ll tmp = 1;
    while(tmp < 1e9){
        ans += 1.0/tmp;
        i++;
        tmp = pow(i, n);
    }
    cout << fixed << setprecision(15);
    cout << ans << endl;
    return 0;
}