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<stdlib.h>

int main(void){

  int N,K;
  
  char S[51];

  scanf("%d %d\n",&N,&K);
  
  scanf("%s\n",S);
  
  for(int i=0;i<N;i++){
  	if(i!=K-1){
    	printf("%c",S[i]);
    }else{
    	printf("%c",S[i]+32);
    }
  }


  return 0;
}