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,
    marker::{Chars, Usize1},
};

fn main() {
    input! {
        n: usize,
        k: Usize1,
        mut s: Chars,
    }
    match s[k] {
        'A' => s[k] = 'a',
        'B' => s[k] = 'b',
        'C' => s[k] = 'c',
        _ => println!("Input Error"),
    }
    println!("{}", s.into_iter().collect::<String>());
}