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::*;

fn main() {
    input! {
        _n: u32,
        k: usize,
        s: String
    };
    let mut ans = String::new();
    for (index, c) in s.chars().enumerate() {
        if index == k - 1 {
            ans.push_str(&c.to_ascii_lowercase().to_string());
        } else {
            ans.push_str(&c.to_string());
        }
    }
    println!("{}", ans);
}