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;
#define ll long long

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  
  ll n,k; cin >> n >> k; k -= 1;
  string s; cin >> s;
  if (s[k] == 'A') s[k] = 'a';
  else if (s[k] == 'B') s[k] = 'b';
  else s[k] = 'c';
  
  cout << s << endl;
  return 0;
}