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<iostream>
using namespace std;
int main(){
  int n, k;
  cin >> n >> k;
  string s;
  cin >> s;
  
  for(int i=0; i<n; i++){
    if(i+1==k){
      if(s[i]=='A') s[i] = 'a';
      else if(s[i]=='B') s[i] = 'b';
      else s[i] = 'c';
    }
  }
  
  cout << s << endl;  
  return 0;
}