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)

/*
 * main.c
 *
 *  Created on: 2019/05/19
 *      Author: family
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

typedef unsigned long long int uint64_t;
typedef long long int myint64_t;

int main()
{
	int N = 0, K = 0;
	char S[51] = {0};
	scanf("%d %d", &N, &K);
	scanf("%s", S);
	S[K-1] += 0x20;
	printf("%s\n", S);
    return 0;
}