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

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

	vector<bool> v( 1000000 + 1, true );
	for( int i = 2; i <= 100000; i++ ) {
		if( v[i] ) {
			for( int j = 2 * i; j <= 1000000; j += i ) {
				v[ j ] = false;
			}
			v[i] = false;
		}
	}
	int n = 0;
	int ans = 1;
	for( int i = 1; i < 1000000 + 1; i++ ) {
		if( v[i] ) {
			n++;
			if( n >= N ) {
				ans = i;
				break;
			}
		}
	}

	cout << ans << endl;
}