#include <iostream>
#include <vector>
using namespace std;

int main() {
	int N; cin >> N;

	int cnt = 0;
	for (int i = 2;; i++) {
		int x = i;
		vector<pair<int, int>>primes;
		for (int j = 2; j*j <= x; j++) {
			if (x%j == 0) {
				int c = 0;
				while (x%j == 0) {
					x /= j;
					c++;
				}
				primes.push_back(make_pair(j, c));
			}
		}
		if (x != 1)primes.push_back(make_pair(x, 1));

		bool flag = true;
		if (primes.size()>2)flag = false;
		if (primes.size() == 1) {
			if (primes[0].second == 3) {
				cnt++;
				if (cnt == N) {
					cout << i << endl;
					break;
				}
			}
			flag = false;
		}

		if (flag == false)continue;
		if (!(primes[0].second == 1 && primes[1].second == 1))flag = false;

		if (flag) {
			cnt++;
			if (cnt == N) {
				cout << i << endl;
				break;
			}
		}
	}
	return 0;
}