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 Rust (1.42.0) (judge verdict: Accepted)

use proconio::input;
use proconio::marker::{Chars, Usize1};

fn main()
{
    input! {
    _n:usize,
    k:Usize1,
    mut s:Chars,
    }

    let ans = s.into_iter().enumerate().map(|(i, c)| {
        if i == k {
            c.to_ascii_lowercase()
        } else {
            c
        }
    }).collect::<String>();
    println!("{}", ans);
}