ModAdd

import fileinput
#import time

#t1 = time.time()

with fileinput.input(['-']) as input:
    a = input.readline().rstrip()
    b = input.readline().rstrip()
    len_a = len(a)
    len_b = len(b)
    res = []
    d = {}
    z = min(len_a, len_b)
    for i in range(-z, 0):
        a_i = int(a[i])
        b_i = int(b[i])
        if (a_i, b_i) not in d:
            d[(a_i, b_i)] = str((int(a[i]) + int(b[i])) % 10)
        res.append(d[a_i, b_i])
    if len_a > len_b:
        res = list(a[0:len_a - z]) + res
    elif len_a < len_b:
        res = list(b[0:len_b - z]) + res
    print(''.join(res))

#t2 = time.time()

#print(t2-t1)

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: TIME LIMIT EXCEEDED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: TIME LIMIT EXCEEDED

Test 8

Verdict: TIME LIMIT EXCEEDED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED