int_1, int_2 = list(map(int, input().split()))

answer = int_1 + int_2



if 10 <= answer:

    print('error')

else:

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

answer = a + b

print(('error' if 10 <= answer else answer))
int_1, int_2 = list(map(int, input().split()))
answer = int_1 + int_2
if 10 <= answer:
    print("error")
else:
    print(answer)

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

-int_1, int_2 = list(map(int, input().split())) -answer = int_1 + int_2 -if 10 <= answer: -    print("error") -else: -    print(answer) +a, b = list(map(int, input().split())) +answer = a + b +print(("error" if 10 <= answer else answer))