Problem:
Score : 100 points

Problem Statement

You are given a string S of length N consisting of A, B and C, and an integer K which is between 1 and N (inclusive).
Print the string S after lowercasing the K-th character in it.

Constraints

1 ≤ N ≤ 50

1 ≤ K ≤ N

S is a string of length N consisting of A, B and C.

Input

Input is given from Standard Input in the following format:

N K
S

Output

Print the string S after lowercasing the K-th character in it.

Sample Input 1

3 1
ABC

Sample Output 1

aBC

Sample Input 2

4 3
CABA

Sample Output 2

CAbA

Solution in PHP (5.6.30) (judge verdict: Accepted)

<?php
 fscanf(STDIN,"%d %d",$a,$b);
 $pointsN = trim(fgets(STDIN));
 $arr1 = explode(" ", $pointsN);
 $arrN = str_split($arr1[0]);
 $arrN[$b-1] = strtolower($arrN[$b-1]);
 for($i=0; $i<$a; $i++){
   echo $arrN[$i];
 }
 ?>