class Solution:
def countSubstrings(self, s: str) -> int:
ans = 0
s = '.' + '.'.join(s) + '.'
for i in range(len(s)):
l = 1
while i - l >= 0 and i + l < len(s) and s[i - l] == s[i + l]:
l += 1
ans += l // 2
return ans