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;
  cin >> n >> k;
  vector<char>c(n);
  
  for (int i = 0; i < n; i++)
  {
    cin >> c.at(i);
  }
  
  k -= 1;
  
  if (c.at(k) == 'A')
    c.at(k) = 'a';
  if (c.at(k) == 'B')
    c.at(k) = 'b';
  if (c.at(k) == 'C')
    c.at(k) = 'c';
  
  for (int i = 0; i < n; i++)
    cout << c.at(i);
  
  cout << endl;
}