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 Pascal (FPC 2.6.2) (judge verdict: Wrong Answer)

var str:array[1..52]of char;
    n,k,i:integer;
begin
  readln(n,k);
  for i:=1 to n do read(str[i]);
  if str[k]='A' then str[k]:='a';
  if str[k]='B' then str[k]:='b';
  if str[k]='C' then str[k]:='c';
  for i:=1 to n do writeln(str[i]);
end.