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: Runtime Error)

var c : array[1..20] of char;
    n, k : integer;
    i : integer;
begin
  read(n, k);
  readln();
  for i := 1 to n do read(c[i]);
  if c[k] = 'A' then c[k] := 'a';
  if c[k] = 'B' then c[k] := 'b';
  if c[k] = 'C' then c[k] := 'c';
  for i := 1 to n do write(c[i]);
end.