import java.util.*;public class Main {public static void main(String[] args) {Scanner yomi = new Scanner(System.in);int[] suuzi = new int[2];for (int i=0;i<2;i++){suuzi[i]=yomi.nextInt();}if (suuzi[0]<10 && suuzi[1]<10){System.out.println(suuzi[0]*suuzi[1]);}else System.out.println(-1);}}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz