#include <bits/stdc++.h> using namespace std; int main() { int n; double a = 0; cin >> n; for (int i = 1; i <= n; ++ i) { long long q = 1; for (int j = 1; j <= i; ++ j) q *= j; a += 1.0 / q; } cout << fixed << setprecision(10) << a; return 0; }