#include <iostream>
#include <cmath>

int main()
{
	int k = 0, ok = 1, x, d;
	std::cin >> x;
	unsigned long long limita = 18446744073709551615;
	if (x == 1)
		std::cout << "2";
	else
	{
		for (unsigned long long i = 2; i <= limita && x != k; i++)
		{
			for (unsigned long long j = 2; j <= sqrt(i) && ok == 1; j++)
				if (i % j == 0)
					ok = 0;
			if (ok == 1)
			{
				k++;
				d = i;
			}
			ok = 1;
		}
		std::cout << d;
	}
	return 0;
}