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)

"use strict";
function I(t,i){this._s=t.split("\n"),this._c=0,this._l=0,this._f=i||Number}I.prototype.a=function(t){var i=this._s[this._l];if(i){var s=i.trim().split(" "),h=s[this._c];return this._c++,s.length===this._c&&(this._c=0,this._l++),t?t(h):this._f(h)}},I.prototype.l=function(t){var i=this._s[this._l];if(i)return this._c=0,this._l++,i.split(" ").map(t||this._f)},module.exports=I;

function main(input) {
  var o = new I(input);

  var n = o.a();
  var k = o.a();
  var s = o.a(String);

  s = s.split("");
  s[k - 1] = s[k - 1].toLowerCase();
  s = s.join("");
  console.log(s);
}


main(require("fs").readFileSync("/dev/stdin", "utf8"));