a = list(input())
b = list(input())

a.reverse()
b.reverse()


ans = 0
for i in range(32):
    b1 = 0

    if len(a) > i:
        if a[i] == '1':
            b1 = 1

    b2 = 0

    if len(b) > i:
        if b[i] == '1':
            b2 = 1

    ans += (b1 ^ b2) << i

print(ans)