import java.util.*; public class Main { public static void main (String[] args) { Scanner sc = new Scanner(System.in); long n = sc.nextLong(); for (long i = 3; i <= Math.sqrt(n); i++) { if (n % i == 0) { System.out.println(i); return; } } if (n % 2 == 0 && n != 4) { System.out.println(n / 2); } else { System.out.println(n); } } }