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

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

    int s = 0, i = 1;
    while (s < n) {
        int ok = 1;
        for (int j = 2; j < i; ++j)
            if (i % j == 0 && j != 2 && j != 3 && j != 5 && j != 7) {
                ok = 0;
                break;
            }
        if (ok) ++s;
        if (s == n) { cout << i << '\n'; break; }
        ++i;
    }
    return 0;
}
/**************************************************************
	Problem: 1874
	User: admin
	Language: C++
	Result: Wrong Answer
****************************************************************/