python 实现输入一段英文，找出其中出现次数最多的单词，打印出出现最多的单词和次数

import re

st = input('请输入内容:')
words = re.findall('[a-zA-Z]+', st)
words1=list(set(words))
word_dict={}
for key in words1:
    word_dict[key] = 0
for key  in word_dict:
    for word in words:
        if key == word:
            word_dict[key] += 1

for key, val in word_dict.items():
    if val == max(word_dict.values()):
        print(key,val)

pass

运行结果：
请输入内容: a a b, c, c
c 2
a 2