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: Accepted)

i = list(map(int,(input().split())))
word = list(input())
#print(word)
count = 0
ans = []
for n,moji in enumerate(word):
  if n == (i[1]-1):
    ans.append(moji.lower())
  else:
    ans.append(moji)
    
print(('').join(ans))