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)

function Main(input) {
  input = input.trim()
  input = input.split("\n");
  var N = input[1].split("");
  var A = input[0].split(" ").map(Number);
  N[A[1]-1] = hoge(N[A[1]-1]);
  
  console.log(N.join(""))

}Main(require("fs").readFileSync("/dev/stdin", "utf8"));
function hoge(N){
switch(N){
  case "A":
  return "a";
  break;
    case "B":
  return "b";
  break;
    case "C":
  return "c";
  break;
}
}