output_description: Print the desired string in one line.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      S
      w
attempt: def getinputdata():
  
      # 配列初期化
      array_result = []
  
      data = input()
  
      array_result.append(data.split(" "))
  
      flg = 1
  
      try:
  
          while flg:
  
              data = input()
              if data != "":
  
                  array_result.append(data.split(" "))
  
              else:
  
                  flg = 0
      finally:
  
          return array_result
  
  
  arr_data = getinputdata()
  
  s = arr_data[0][0]
  w = int(arr_data[1][0])
  
  result = [s[i] for i in range(0, len(s), w)]
  
  print("".join(result))
  
problem_description: Statement
  
  You are given a string S consisting of lowercase English letters. We will
  write down this string, starting a new line after every w letters. Print the
  string obtained by concatenating the letters at the beginnings of these lines
  from top to bottom.
samples: [{"input": "abcdefgh\n    3", "output": "adg\n    \n\nWhen we write down `abcdefgh`, starting a new line after every three letters,\nwe get the following:\n\nabc  \ndef  \ngh\n\nConcatenating the letters at the beginnings of these lines, we obtain `adg`.\n\n* * *"}, {"input": "lllll\n    1", "output": "lllll\n    \n\n* * *"}, {"input": "souuundhound\n    2", "output": "suudon"}]