Какое количество раз слово встречается в строке

from collections import Counter
a = 'In a hole in the ground there lived a ground like at the 5-th stars ground'.lower()
max_word = max((x for x in re.findall(r'\w+', a)), key=len)
mw = Counter(map('lower()', filter(map('strip()', '\w+'.split()), max_word)))

a = 'In a hole in the ground there lived a ground like at the 5-th stars ground'
len(re.findall(r'\b{}\b'.format(input()), a))

a.split().count(input())

>>> a = 'Three one two one, and three one.'
>>> a.split().count(input())
one
1
>>> len(re.findall(r'\b{}\b'.format(input()), a))
one
3
>>>

[w.rstrip(',.!?:;') for w in a.split()].count('one')

sum(w.rstrip(',.!?:;') == 'one' for w in a.split())

len(1 for w in a.split() if w.rstrip(',.!?:;') == 'one')

from collections import Counter
s = 'In a hole in the ground there lived a ground like at the 5-th stars ground'.lower()
l = s.split()
c = Counter(l)

с('ground') вернёт 3, в вашем случае

s = 'In a hole in the ground there lived a ground like at the 5-th stars ground.'.lower()

a = 'Three one two one, and three one.'.lower()
print(sum(1 for w in a.split() if w.rstrip(',.!?:;') == 'one'))