ModAdd

import fileinput

with fileinput.input(['-']) as input:
    a = list(input.readline().rstrip())[::-1]
    b = list(input.readline().rstrip())[::-1]
    res = []
    for i in range(max(len(a), len(b))):
        try:
            a_i = int(a[i])
        except IndexError:
            res += b[i:]
            break
        try:
            b_i = int(b[i])
        except IndexError:
            res += a[i:]
            break
        res.append(str((a_i + b_i) % 10))
    print(int(''.join(res[::-1])))

Test 1

Verdict: ACCEPTED

Test 2

Verdict: TIME LIMIT EXCEEDED

Test 3

Verdict: TIME LIMIT EXCEEDED

Test 4

Verdict: TIME LIMIT EXCEEDED

Test 5

Verdict: TIME LIMIT EXCEEDED

Test 6

Verdict: TIME LIMIT EXCEEDED

Test 7

Verdict: TIME LIMIT EXCEEDED

Test 8

Verdict: TIME LIMIT EXCEEDED

Test 9

Verdict: TIME LIMIT EXCEEDED

Test 10

Verdict: TIME LIMIT EXCEEDED