class Solution:
def countWords(self, words1: List[str], words2: List[str]) -> int:
map1, map2 = {}, {}
cnt = 0
for word in words1:
map1[word] = map1.get(word, 0) + 1
for word in words2:
map2[word] = map2.get(word, 0) + 1
for word in set(words1) & set(words2):
if map1[word] == 1 and map2[word] == 1:
cnt += 1
return cnt
