Why isn't it working properly??

Question

a = input()
for k in range(len(a)+1):
if a[:k] == a[k::-1]:
print(a[k::-1])

Answer 1

len(a)-1

Answer 2

Shahir How about this one? :-

a = input()
for i in range(len(a) - 1, -1, -1):
if a[:i+1] == a[i::-1]:
print(a[:i+1])
break

# Hope this

Answer 3

Given a string s, return the longest palindromic substring in s
Input: s = "babad"
Output: "bab"
Note: "aba" is also a valid answer