```
class Solution(object):
def getHint(self, secret, guess):
"""
:type secret: str
:type guess: str
:rtype: str
"""
s = []
g = []
l = len(secret)
a = 0
b = 0
for i in range(l):
if guess[i] == secret[i]:
a += 1
else:
s.append(secret[i])
g.append(guess[i])
for j in range(len(g)):
if g[j] in s:
b += 1
s.remove(g[j])
a = str(a)
b = str(b)
hint = a+'A'+b+'B'
return hint
```