def calendar(array):

  final = []
  array.sort();
  biggest = [array[0][0], array[0][1]]
  no_match = True

  for i in range(0, len(array)):
    min_i = array[i][0]
    max_i = array[i][1]

    for j in range((i+1), len(array)):
      min_j = array[j][0]
      max_j = array[j][1]

      if (min_j <= max_i) & (max_j > max_i):

        final.append([min_i, max_j])
        no_match = False
        pass

      if (no_match == True) & (j == (len(array) - 1)):

        if (biggest[1] > min_j) & (biggest[1] > max_j):

          break
        else:

          biggest = array[i]
          final.append(array[i])
          no_match = True
          break

  if not final:
    final = biggest
    return final
  else:
    return final

print(calendar([(1, 10), (2, 6), (3, 5), (7, 9)]))