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'

const main = input => {
	const args = input.trim().split('\n')
	const k = parseInt(args[0].split(' ')[1], 10)
	const s = args[1]
	console.log(`${s.slice(0, k - 1)}${s.slice(k - 1, k).toLowerCase()}${s.slice(k)}`)
}

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