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 (1.15.1) (judge verdict: Accepted)

use std::io::*;
         
fn main() {
        	
     let mut nk = String::new();
     let mut s = String::new();
         
     stdin().read_line(&mut nk).unwrap();
     stdin().read_line(&mut s).unwrap();
         
     let k: usize = nk.trim().split_whitespace().collect::<Vec<_>>()[1].parse::<usize>().unwrap();
         
     let mut s = s.trim().chars().collect::<Vec<char>>();
     s[k - 1] = (s[k-1] as u8 + 32) as char;
     
     println!("{}", s.into_iter().collect::<String>());
}