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 C (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#define lop(i, n) for(i=0; i<n; i++)

int main()
{
	int n,k,i;
	char s[50];
	
	scanf("%d %d", &n, &k);
	scanf("%s", s);
	
	s[k-1]=tolower(s[k-1]);
	
	printf("%s", s);
	
return 0;
}