#include<iostream> #include<vector> #include<iomanip> #define ll long long using namespace std; int main(){ cout << fixed << setprecision(15); int n; cin >> n; long double sum = 0; for(int i = 1;i <= n;i++){ long double x = 1/(long double)i; sum += x; } sum /= (long double)n; cout << sum << endl; return 0; }