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: Accepted)

fun main(args: Array<String>) {
    val (x, y) = readLine()!!.split(" ").map { it.toInt() }
    val s = readLine()!!.toMutableList()
    when(s[y - 1]){
        'A' -> s[y - 1] = 'a'
        'B' -> s[y - 1] = 'b'
        'C' -> s[y - 1] = 'c'
    }
    for(i in 0 until x){
        print(s[i])
    }
}