ModAdd

import fileinput

with fileinput.input(['z']) as input:
    a = list(input.readline().rstrip())
    b = list(input.readline().rstrip())
    res = []
    if len(a) > len(b):
        for i in range(len(a) - len(b)):
            b = ['0'] + b
    elif len(b) > len(a):
        for i in range(len(b) - len(a)):
            a = ['0'] + a
    for i in range(len(a)):
        res.append(str((int(a[i]) + int(b[i])) % 10))
    print(int(''.join(res)))

Test 1

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 4, in <module>
    a = lis...

Test 2

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 4, in <module>
    a = lis...

Test 3

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 4, in <module>
    a = lis...

Test 4

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 4, in <module>
    a = lis...

Test 5

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 4, in <module>
    a = lis...

Test 6

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 4, in <module>
    a = lis...

Test 7

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 4, in <module>
    a = lis...

Test 8

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 4, in <module>
    a = lis...

Test 9

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 4, in <module>
    a = lis...

Test 10

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 4, in <module>
    a = lis...