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: Runtime Error)

function Main(input) {
	
	input = input.split("\n");
	tmp = input[0].split(" ");
    
    var n = tmp[0];
    var k = tmp[1];
    var s = input[1];
    var l = s.length;
    var rs = [];
    var res;

    for(var i = 0; i < l; i++){
        rs = s[i];
    }

    rs[k] = rs[k].toLowerCase();

    for(var i = 0; i < l; i++){
        res += rs[i];
    }
    console.log(res);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));