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.

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.

Constraints

• 1 ≤ N ≤ 50
• 1 ≤ K ≤ N
• S is a string of length N consisting of A, B and C.

Sample Input 1

3 1
ABC

Sample Output 1

aBC

Sample Input 2

4 3
CABA

Sample Output 2

CAbA

见题面 Input 部分

见题面 Output 部分