A = input().strip()
B = input().strip()

max_len = max(len(A), len(B))

A_padded = A.zfill(max_len)
B_padded = B.zfill(max_len)

result = []
for a, b in zip(A_padded, B_padded):
    sum_bit = (int(a) + int(b)) % 2
    result.append(str(sum_bit))

binary_result = ''.join(result)
decimal_result = int(binary_result, 2)

print(decimal_result)