#include <iostream>
#include <numeric>
#include <cmath>
#include <limits>
#include <stdio.h>
#include <iomanip>
#include <string> // string, to_string, stoi
#include <vector> // vector
#include <algorithm> // min, max, swap, sort, reverse, lower_bound, upper_bound
#include <utility> // pair, make_pair
#include <tuple> // tuple, make_tuple
#include <cstdint> // int64_t, int*_t
#include <cstdio> // printf
#include <map> // map
#include <queue> // queue, priority_queue
#include <set> // set
#include <stack> // stack
#include <deque> // deque
#include <unordered_map> // unordered_map
#include <unordered_set> // unordered_set
#include <bitset> // bitset
#include <cctype> // isupper, islower, isdigit, toupper, tolower
using namespace std;
using ll = long long;
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
ll Max(ll(a), ll(b), ll(c)) {
	return max(max(a, b), c);
}
ll Min(ll(a), ll(b), ll(c)) {
	return min(min(a, b), c);
}


bool kai(ll A, ll B, ll T,ll N,vector<ll> H) {
	ll an = 0;
	rep(i, N) {
		if (H[i] > B * T) {
			an += max(((H[i] - B * T - 1) / (A - B)) + 1, ll(0));
		}
	}
	if (an <= T) return true;
	else return false;
}
bool isOK(ll A, ll B, ll T, ll N, vector<ll> H) {
	if (kai(A,B,T,N,H)) return true;
	else return false;
}
ll binary_search(ll A,ll B,ll N, vector<ll> H) {
	int left = 0; 
	int right = 1e13; 
	while (right - left > 1) {
		int mid = left + (right - left) / 2;

		if (isOK(A,B,mid,N, H)) right = mid;
		else left = mid;
	}

	/* left は条件を満たさない最大の値、right は条件を満たす最小の値になっている */
	return right;
}
ll ketawa(ll N) {
	ll ans = 0;
	while (N > 0) {
		ans += N % 10;
		N /= 10;
		
	}
	return ans;
}
int main() {
	cout << fixed << setprecision(20);
	double N;
	cin >> N;
	double an = 0;
	for (double i = 1; i < 1e7 / N; i++) {
		double d = i;
		double k = 1;
		rep(j, N) {
			k *= d;
		}
		an += double(1 / k);
	}
	cout << an << endl;
}