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 Kotlin (1.0.0) (judge verdict: Wrong Answer)

import java.util.*

fun main(args: Array<String>) {
    val sc = Scanner(System.`in`)
    val n = sc.nextInt()
    val k = sc.nextInt()
    val s = sc.next().toString()

    println(abc126a(n, k, s))
}

fun abc126a(n: Int, k: Int, s: String): String {
    var ans = ""
    for (i in 0..n - 1) {
        if (i == k) {
            ans += s[i].toLowerCase()
        } else {
            ans += s[i].toString()
        }
    }

    return ans
}