def birthday(s, d, m):
# Write your code here
count = 0
for i in range(len(s) + 1 - m):
if (sum(s[i:i+m]) == d): count+=1
return(count)
def strings_xor(s, t):
res = ""
for i in range(len(s)):
if s[i] == t[i]:
res += '0';
else:
res += '1';
return res
s = input()
t = input()
print(strings_xor(s, t))