output_description: Print the string S after lowercasing the K-th character in it.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K
      S
attempt: N, M = input().split()
  N = int(N)
  M = int(M)
  list = []
  A_list = []
  
  for i in range(M):
      x, y, z = input().split()
      x, y, z = int(x), int(y), int(z)
      list.append([x, y, z])
  
  A_list.append([list[0][0]])
  for data in list:
      check = 0
      for A_data in A_list:
          if data[0] in A_data:
              A_data.append(data[1])
              check = 0
          elif data[1] in A_data:
              A_data.append(data[0])
              check = 0
          elif not data[0] in A_data and not data[1] in A_data:
              check = 1
      if check:
          A_list.append([data[0], data[1]])
  
  print(len(A_list))
  
problem_description: 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.
samples: [{"input": "3 1\n    ABC", "output": "aBC\n    \n\n* * *"}, {"input": "4 3\n    CABA", "output": "CAbA"}]