text: """
  Read file into texts and calls.
  It's ok if you don't understand how to read files.
  """
  import csv
  
  with open('texts.csv', 'r') as f:
      reader = csv.reader(f)
      texts = list(reader)
  
  with open('calls.csv', 'r') as f:
      reader = csv.reader(f)
      calls = list(reader)
  
  """
  TASK 3:
  (080) is the area code for fixed line telephones in Bangalore.
  Fixed line numbers include parentheses, so Bangalore numbers
  have the form (080)xxxxxxx.)
  
  Part A: Find all of the area codes and mobile prefixes called by people
  in Bangalore.
   - Fixed lines start with an area code enclosed in brackets. The area
     codes vary in length but always begin with 0.
   - Mobile numbers have no parentheses, but have a space in the middle
     of the number to help readability. The prefix of a mobile number
     is its first four digits, and they always start with 7, 8 or 9.
   - Telemarketers' numbers have no parentheses or space, but they start
     with the area code 140.
  
  Print the answer as part of a message:
  "The numbers called by people in Bangalore have codes:"
   <list of codes>
  The list of codes should be print out one per line in lexicographic order with no duplicates.
  
  Part B: What percentage of calls from fixed lines in Bangalore are made
  to fixed lines also in Bangalore? In other words, of all the calls made
  from a number starting with "(080)", what percentage of these calls
  were made to a number also starting with "(080)"?
  
  Print the answer as a part of a message::
  "<percentage> percent of calls from fixed lines in Bangalore are calls
  to other fixed lines in Bangalore."
  The percentage should have 2 decimal digits
  """
  # Part A
  called_numbers = []
  for i in range(len(calls)):
      if calls[i][0][:5] == '(080)':
          if calls[i][1][0] == '(':
              par_index = calls[i][1].find(')')
              called_numbers.append(calls[i][1][:par_index+1])
          elif calls[i][1][:3] == '140':
              called_numbers.append('140')
          else:
              called_numbers.append(calls[i][1][:4])
  
  l = len(called_numbers)
  count = called_numbers.count('(080)')
  called_numbers = sorted(set(called_numbers))
  print("The numbers called by people in Bangalore have codes:")
  for code in called_numbers:
      print(code)
  
  # Part B
  percent = count * 100 / l
  print("{} percent of calls from fixed lines in Bangalore are calls to other fixed lines in Bangalore.".format(round(percent, 2)))