#include<bits/stdc++.h>
using namespace std;
long const mod = 1e9+7;
int main(){
    long n;
    cin >> n;
    double ans = 0.0;
    for(double i = 1;i<=100;i += 1.0){
        double tmp = 1.0;
        for(int j=0;j<n;j++){
            tmp *= (1.0/i);
        }
        ans += tmp;
    }
    printf("%.10lf",ans);
}