input: Write a python function to remove overlapping words from two strings and join the result.
  assert remove_overlap("apple banana cherry", "banana cherry date") == "apple banana cherry date"
  assert remove_overlap("one two three", "three four five") == "one two three four five"
  assert remove_overlap("hello world", "world peace") == "hello world peace"
output: def remove_overlap(str1, str2):
      words1 = str1.split()
      words2 = str2.split()
      combined_words = words1 + [word for word in words2 if word not in words1]
      return ' '.join(combined_words)