A, B = list(map(int, input().split()))



if A >= 10 or B >= 10:

    print((-1))

    exit()



ans = A * B

print(ans)
A, B = list(map(int, input().split()))



if 1 <= A <= 9 and 1 <= B <= 9:

    print((A*B))

else:

    print((-1)) 
A, B = list(map(int, input().split()))
if A >= 10 or B >= 10:
    print((-1))
    exit()
ans = A * B
print(ans)

A, B = list(map(int, input().split()))
if 1 <= A <= 9 and 1 <= B <= 9:
    print((A * B))
else:
    print((-1))

-if A >= 10 or B >= 10: +if 1 <= A <= 9 and 1 <= B <= 9: +    print((A * B)) +else: -    exit() -ans = A * B -print(ans)