def Decimal(Binary):
    ans = 0
    for i in range(len(Binary)):
        ans += int(Binary.pop()) * 2**i
    print(ans)


def Cal(length, B_1, B_2):
    Binary = [0 for i in range(length)]
    for i in range(len(B_1) - 1, -1, -1):
        if B_2:
            P_1, P_2 = int(B_1.pop()), int(B_2.pop())
            if P_1 + P_2 == 2:
                Binary[i] = "0"
            else:
                Binary[i] = str(P_1 + P_2)
        else:
            P_1 = int(B_1.pop())
            Binary[i] = str(P_1)
    return Binary


B_1 = list(str(input()))
B_2 = list(str(input()))
if len(B_2) > len(B_1):
    B_1, B_2 = B_2, B_1
Binary = Cal(len(B_1), B_1, B_2)
Decimal(Binary)