class Solution:

# Time: O(n)

# Space: O(n)

def reverse_only_letters(self, s: str) -> str:

chars = list(s)

left, right = 0, len(chars) - 1

while left < right:

if not chars[left].isalpha():

left += 1

elif not chars[right].isalpha():

right -= 1

else:

chars[left], chars[right] = chars[right], chars[left]

left += 1

right -= 1

return "".join(chars)