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 Perl (v5.18.2) (judge verdict: Accepted)

use strict;
use warnings;

my $line = <STDIN>;
chomp($line);

my ($N, $K) = split(q{ }, $line);

my $str = <STDIN>;
chomp($str);

my @str_array = split(q{}, $str);
$str_array[$K-1] = lc($str_array[$K-1]);

print join(q{}, @str_array);