B. Vera And LCS
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

Vera is learning about the longest common subsequence problem.

A string is a (possibly empty) sequence of lowercase letters. A subsequence of a string S is a string obtained by deleting some letters of S (possibly none or all). For example "vra", "a", "", and "vera" are all subsequences of "vera". The longest common subsequence (LCS) of two strings A, B is a string that is a subsequence of A and B and has the maximum length among all strings that are a subsequence of A and B. There could be multiple LCS for two given strings. For example a LCS of "vera" and "eats" is "ea".

For homework she was given two strings A, B, both of length N and she had to determine the length of the LCS of A and B. She determined the answer to be K but lost B. Given A and K, help her find a possible value of B. It's possible that Vera may have made a mistake and no such B exists, in that case output "WRONGANSWER" (without quotes).

Constraints:

1 ≤ N ≤ 2000

0 ≤ K ≤ 2000

N, K are integers

A consists of N lowercase letters

Input

The input will be in the format:

N K

A

Output

Output one line consisting of the string B of N lowercase letters, or "WRONGANSWER" if no B is valid. If there are multiple correct B output any of them.

Examples
Input
4 2
vera
Output
eats
Input
4 5
vera
Output
WRONGANSWER
Note

For the first example, another possible answer is "uber".