import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();
		int y = sc.nextInt();
		int res = 4 * x + 3 * y;
		if (res % 2 != 0) {
			System.out.println("impossible");
		} else {
			System.out.println("possible");
		}
		sc.close();
	}
}