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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
using namespace std;

int main(){
  int N,K;
  string S;
  cin >>N>>K>>S;
  
  switch (S.at(K-1)) {
    case 'A':
	  S.at(K-1)='a';
      break; 
		
	case 'B':
        S.at(K-1)='b';
      break; 
      
    case 'C':
		  S.at(K-1)='c';
      break; 
		
	default:
		break;
	}
  
cout <<S<<endl;
}