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)

let n, k, s = Scanf.scanf " %d %d %s" @@ fun a b c -> a, b - 1, c
let _ = print_endline @@ String.mapi (fun i c -> if i = k then Char.lowercase c else c) s