# include <fstream>
using namespace std;
# define N (2*i+1)
int k, v[100000000], n=0;
ofstream fout ("prim.out");

void erat ()
{
	int j, i, c=1;
	for (i=1;c<k;i++)
		if (!v[N])
		{
			c++;
			for (j=2;j<=2*N;j++)
				v[j*N]=1;
		}
	for (;!n;i++)
		if (!v[N])
			n=N*N;
}

int main ()
{
	ifstream fin ("prim.in");
	fin>>k;
	erat();
	fout<<n;
	return 0;
}