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() {
	char s[80];
	int i,n,k;
	scanf("%d", &n);
	scanf("%d", &k);
	scanf("%s", s);
	i = 0;
	while (s[i]) {
		if ((i + 1) != k) {
			printf("%c", s[i]);
		} else {
			printf("%c", s[i] - 'A' + 'a');
		}		
		i++;
	}
	printf("\n");
	return 0;
}