#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() {
	ll k;
	cin >> k;
	long double ans = 0;
	ll n = 1;
	rep(i, 1000000) {
		ans += sin(n * k) / pow(n, n);
		n++;
	}
	cout << fixed << setprecision(12) << ans << endl;
}