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 Ruby (2.3.3) (judge verdict: Wrong Answer)

s = gets.to_i

a = s/100
b = s%100
 
if a.between?(1, 12) & b.between?(1, 12)
  puts 'AMBIGUOUS'
elsif !a.between?(1, 12) & !b.between?(1, 12)
  puts 'NA'
elsif !a.between?(1, 12) & b.between?(1, 12)
  puts 'YYMM'
else
  puts 'MMYY'
end