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: Wrong Answer)

#include <iostream>
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iostream>
#include <vector>
#include <numeric>
#include <string>
#include <functional>
#include <iostream>
#include <cstdlib>
#include <algorithm>
#include <cctype>
#include <iostream>
#include <string>
#include <algorithm>
#include <string>

using namespace std;
     
int main() {
  int n,b;
  cin >> n >> b;
  std::string s;
  cin >> s;
        
  char cary[n]; 
  s.copy(cary, n);
      
  for (int i=0;i<n;i++){
    if (i == b-1) {
      cary[i] = std::tolower(cary[i]);
    }
  }
     
  cout << cary << endl;    
  return 0;
}