input: Write a function to find the maximum length of the combined prefix from two sorted lists.
  assert findMaxLen([1, 3, 5, 7], [2, 3, 4, 5, 7]) == 3
  assert findMaxLen([1, 4, 6], [2, 3, 5, 6]) == 1
  assert findMaxLen([1, 2, 3], [4, 5, 6]) == 0
output: def findMaxLen(list1, list2):
      i, j = 0, 0
      max_len = 0
      while i < len(list1) and j < len(list2) and list1[i] == list2[j]:
          i += 1
          j += 1
          max_len += 1
      return max_len