Longest Palindrome

class Solution:
    def longestPalindrome(self, s: str) -> int:
        dict={}
        for i in s:
            dict[i]=dict.get(i,0)+1
        ans=0
        for k,v in dict.items():
            if v%2==1:
                if ans%2==0: #atleast one character can be kept in centre
                    ans+=v
                else:
                    ans+=v-1
            else:
                ans+=v
        return ans