Given two equal-size strings s and t. In one step you can choose any character of t and replace it with another character.
Return the minimum number of steps to make t an anagram of s.
An Anagram of a string is a string that contains the same characters with a different (or the same) ordering.
Example 1:
Input: s = "bab", t = "aba"
Output: 1
Explanation: Replace the first 'a' in t with b, t = "bba" which is anagram of s.
Example 2:
Input: s = "leetcode", t = "practice"
Output: 5
Explanation: Replace 'p', 'r', 'a', 'i' and 'c' from t with proper characters to make t anagram of s.
Example 3:
Input: s = "anagram", t = "mangaar"
Output: 0
Explanation: "anagram" and "mangaar" are anagrams. 
Example 4:
Input: s = "xxyyzz", t = "xxyyzz"
Output: 0
Example 5:
Input: s = "friend", t = "family"
Output: 4
Constraints:
1 <= s.length <= 50000
s.length == t.length
s and t contain lower-case English letters only.
class Solution:
    def minSteps(self, s: str, t: str) -> int:
        help_dict = defaultdict(int)
        res = 0
        
        for char in s:
            help_dict[char] += 1
        
        for char in t:
            if help_dict[char] > 0:
                help_dict[char] -= 1
            else:
                res += 1
                
        return res
class Solution:
    def minSteps(self, s: str, t: str) -> int:
        help_dict = defaultdict(int)
        res = 0
        
        for char in s:
            help_dict[char] += 1
        
        for char in t:
            if help_dict[char] > 0:
                help_dict[char] -= 1
            else:
                res += 1
                
        return res