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: Runtime Error)

#ABC126 B

S = list(map(int,input()))
if 1 <= S[0]*10 + S[1] <= 12 and 1 <= S[2]*10 + S[3] <= 12:
    print("AMBIGUOUS")
elif 1 <= S[0]*10 + S[1] <= 12 and (S[2]*10 + S[3] > 12 or S[2]*10 + S[3] == 0):
    print("MMYY")
elif (S[0]*10 + S[1] > 12 or S[0]*10 + S[1] == 0)  and  1 <= S[2]*10 + S[3] <= 12:
    print("YYMM")
elif (S[0]*10 + S[1] > 12 or S[0]*10 + S[1] == 0) and (S[2]*10 + S[3] > 12 or S[2]*10 + S[3] == 0):
    print("NA")