- Time limit: 1.00 s
- Memory limit: 512 MB
aybabtu
is bab
.Input
The only input line contains a string of length $n$. Each character is one of a–z.
Output
Print the longest palindrome in the string. If there are several solutions, you may print any of them.
Constraints
- $1 \le n \le 10^6$
Input:
aybabtu
Output:
bab