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: Wrong Answer)

#include <stdio.h>

int main(void){
	int n,k,i;
  	char alpha1[26] = {'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
    char alpha2[26] = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
  	scanf("%d %d",&n,&k);
  	char array[51];
  	for(i=0;i<n;i++){
  		scanf("%c",&array[i]);
    }
  	for(i=0;i<26;i++){
    	if(array[k-1] == alpha1[i]){
        	array[k-1] = alpha2[i];
          	break;
        }
    }
  	for(i=0;i<n;i++){
   		printf("%c",array[i]); 
    }
  	printf("\n");
  	return 0;
}