int iszhishu(int k)
{
	int flag = 1;
	for(int i = 2; i < k; i++)
	{
		if(k % i == 0)
		flag = 0;
	}
	return flag;
}

#include<iostream>
using namespace std;
int main()
{
	int n = 0;
	int count = 0;
	cin >> n;
	for (int i = 2; i < 30000; i++)
	{
		if(iszhishu(i))
		{
			count++;
		}
		if(count==n)
		{
			cout << i << endl;
			break; 
		}
	
	}

    return 0;
}