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 9.2.1) (judge verdict: Accepted)

#include<stdio.h>

int main () {
	int n, m;
	scanf("%d %d", &n, &m);
	char s[n];
	scanf("%s", s);
	if(s[m-1] >= 'A' && s[m-1] <= 'Z') {
		s[m-1] += 32;
	} else {
		s[m-1] -= 32;
	}
	printf("%s", s);
	return 0;
}