a, b = list(map(int, input().split()))



answer = a + b



if answer >= 10:

    print('error')

else:

    print(answer)
a, b = list(map(int, input().split()))



if a + b >= 10:

    print('error')

else:

    print((a + b))
a, b = list(map(int, input().split()))
answer = a + b
if answer >= 10:
    print("error")
else:
    print(answer)

a, b = list(map(int, input().split()))
if a + b >= 10:
    print("error")
else:
    print((a + b))

-answer = a + b -if answer >= 10: +if a + b >= 10: -    print(answer) +    print((a + b))