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 <ctype.h>

int main(void)
{
	char S[51];
	int i, N, K;

	scanf("%d %d", &N, &K);
	scanf("%s", S);

	for (i = 0; i < N; i++) {
		if (i == K - 1) {
			S[i] = tolower(S[i]);
		}
	}

	printf("%s\n", S);

	return 0;
}