import string

def decode(m, key):
    p = ""
    for i in range(len(key)):
        if (m[i] == "1" and key[i] == "1"):
            p += str(0)
        elif ((m[i] == "1" and key[i] == "0") or (m[i] == "0" and key[i] == "1")):
            p += str(1)
        else:
            p += str(0)
    return p