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++ (Clang 10.0.0) (judge verdict: Wrong Answer)

#include <iostream>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <cmath>
#define rep(i,n) for (int i = 0; i < n; ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;

int main() {
  int N, K;
  cin >> N >> K;
  string S;
  cin >> S;
  if (S[K-1] == 'A') S[K-1] = 'a';
  if (S[K-1] == 'B') S[K-1] = 'b';
  if (S[K-1] == 'C') S[K-1] = 'c';
  rep(i,N) cout << S[i] << endl;
  return 0;
}