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 (3.4.3) (judge verdict: Wrong Answer)

s = input()
if int(s[:2]) > 12 and int(s[2:]) > 12\
        or s[2:] == "00":
        print("NA")
elif  0 <=  int(s[2:]) < 100 and 1 <= int(s[:2]) <= 12:
        print("YYMM")
elif  1<= int(s[:2]) <= 12 and 0 <= int(s[2:]) < 100:
        print("MMYY")
else:
        print("AMBIGUOUS")