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 JavaScript (node.js v5.12) (judge verdict: Accepted)

const main = (input) => {
  var inputs = input.trim().split("\n");
  var N = inputs[0].split(" ")[0];
  var K = inputs[0].split(" ")[1];
  var A = inputs[1].split("");
  var ans = "";
  for(var i=0;i<N;i++){
    if(K==i+1) ans += A[i].toLowerCase();
    else ans += A[i];
  }
  console.log(ans);
}

main(require('fs').readFileSync('/dev/stdin', 'UTF-8'));