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 Python (3.8.2) (judge verdict: Accepted)

def str_replace_to_lower() -> str:
    len_str, target_index = map(int, input().split())
    word = input()
    list_of_word = list(word)
    list_of_word[target_index - 1] = list_of_word[target_index - 1].lower()

    return ''.join(list_of_word)


print(str_replace_to_lower())