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>

int main() {
	int n,k,i;
	char s[50];
	scanf("%d", &n);
	scanf("%d", &k);
	for(i=0;i<=n;i++) scanf("%c", &s[i]);
	switch (s[k]) {
	case 'A':s[k] = 'a';
		break;
	case 'B':s[k] = 'b';
		break;
	case 'C':s[k] = 'c';
		break;
	}
	for (i = 0; i<=n; i++) printf("%c", s[i]);
}