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++ (GCC 9.2.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
#define REP(i,n) for (int i = 0; i <(n); ++i)
#define ALL(v) v.begin(), v.end()
using namespace std;
using ll = long long;
using P = pair<int,int>;


int main() {
  int n, k;
  cin >> n >> k;
  string s;
  cin >> s;
  --k;

  if(s[k] == 'A') s[k] = 'a';
  if(s[k] == 'B') s[k] = 'b';
  if(s[k] == 'C') s[k] = 'c';

  cout << s << endl;
  return 0;
}