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 OCaml (4.02.3) (judge verdict: Accepted)

open Printf open Scanf
open Array

let () = scanf " %d %d %s" @@ fun n k s ->
  let a = init n (fun i -> s.[i]) in
  a.(k-1) <- Char.lowercase @@ a.(k-1);
  iter (print_char) a