#include <stdio.h>
bool isPrime(int n)
{
    for( int i = 2 ; i*i <= n ; i++ )
        if( n % i == 0 ) return false;
    return true;
}
int main()
{
    freopen(".10.in","r",stdin);
    freopen(".10.out","w",stdout);
	int n, i, j, count=0;
	scanf("%d", &n);
	for( i = 2 ; n ; i++ )
        if( isPrime(i) ) n--;
	printf("%d", i-1);
}