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: Runtime Error)

s = list(input())
a = int(s[0]+s[1])
b = int(s[2]+s[3])
if 0<a<13 and 0<b<13:
    print('AMBIGUOUS')
elif 0<a<13:
    print('MMYY')
elif 0<b<13:
    print('YYMM')
else:
    print('NA')