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 Main(input){
    let temp = input.trim().split('\n');
    let temp2 = temp[0].split(' ').map((v)=>parseInt(v));
    let n = temp2.shift();
    let k = temp2.shift();
    let s = temp[1];

    let ans = s.slice(0,k-1) + s[k-1].toLowerCase() + s.slice(k);
    //s[k-1].toLowerCase();
    console.log(ans);

}
//*この行以降は編集しないでください（標準入出力から一度に読み込み、Mainを呼び出します）
Main(require("fs").readFileSync("/dev/stdin", "utf8"));