def mask_3rd(s):
     if len(s) < 3:
          print(s)
     else:
          third = s[2]
          second = s[:2]
          fourth = s[3:]
          return second.replace(third, "*") + third + fourth.replace(third, "*")

print(mask_3rd("logging"))
print(mask_3rd("apple"))
print(mask_3rd("orange"))
print(mask_3rd("gooooogle"))
print(mask_3rd("i"))