input: Write a Python function that, given a list of integers representing times in hours, returns the number of pairs (i, j) such that i < j and the sum of hours[i] and hours[j] constitutes an exact multiple of 24, thereby forming a complete day.
  
  A complete day is defined as a duration that is a multiple of 24 hours.
  
  For example, 1 day is 24 hours, 2 days is 48 hours, 3 days is 72 hours, etc.
  
  Examples:
  >>> hours = [12,12,30,24,24]
  2
  >>> hours = [72,48,24,3]
  3
  
  Constraints:
  1 <= len(hours) <= 100
  1 <= hours[i] <= 10^9
output: def count_complete_days_pairs(hours):
      count = 0
      n = len(hours)
      for i in range(n):
          for j in range(i + 1, n):
              if (hours[i] + hours[j]) % 24 == 0:
                  count += 1
      return count