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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

"use strict";
const Main = (input) => {
	let xs = input.trim().split(',').toString();
    let A = Number(xs[0] + xs[1]);
    let B = Number(xs[2] + xs[3]);
    
    if(A >= 13 && B <= 13 && A != 0 && B != 0){
       console.log('YYMM');
	}else if(A <= 13 && B >= 13 && A != 0 && B != 0){
       console.log('MMYY');
    }else if(A >= 13 || B >= 13 || A == 0 || B == 0){
       console.log('NA');
    }else if(A <= 13 && B <= 13 && A != 0 && B != 0){
       console.log('AMBIGUOUS');
    }
}
Main(require('fs').readFileSync('/dev/stdin','utf8'));