#include <bits/stdc++.h>
using namespace std;
#include <atcoder/fenwicktree>
using namespace atcoder;

using ll = long long;
#define rep(i, n) for(int i = 0; i < n; i++)

int main() {
	int n;
	cin >> n;
	long double ans = 0;
	ll m = 1;
	rep(i, 1000000) {
		ans += 1.0 / pow(m, n);
		m++;
	}
	cout << fixed << setprecision(12) << ans << endl;
}