import java.util.Scanner;

public class Alabama {

    public static void main(String[] args) {
        Scanner telado = new Scanner(System.in);
        int a = 1, cont = 0,c;
        while (true) {
            for (int i = 1; i <= a; i++) {
                if (a / i == 0) {
                    cont++;
                }
            }
            if (cont == 2) {
                System.out.println(a + " ");
            }
            a++;
            cont = 0;
            c = telado.nextInt();
            if(c == 2){
            System.exit(1);
            }
            else{
            }
        }
    }
}