int number_needed(string a, string b) {
    auto count = 0;
    vector<int> freq(26, 0);
    for (auto c : a) { ++freq[c - 'a']; }
    for (auto c : b) { --freq[c - 'a']; }
    for (auto val : freq) { count += abs(val); }
    return count;
}

from collections import Counter
def number_needed(a, b):
    ct_a = Counter(a)
    ct_b = Counter(b)
    ct_a.subtract(ct_b)
    return sum(abs(i) for i in ct_a.values())

public class Solution {
    public static int numberNeeded(String first, String second) {
        Map<Character, Integer> count = new HashMap<>();
        for( char ch: first.toCharArray() ) {
            int ct = count.containsKey(ch) ? count.get(ch) : 0;
            count.put(ch, (ct + 1));
        }
        
        for( char ch: second.toCharArray() ) {
            int ct = count.containsKey(ch) ? count.get(ch) : 0;
            count.put(ch, (ct - 1));
        }
        
        List<Integer> values = new ArrayList<>( count.values() );
        int total = 0;
        for( Integer v: values ) {
            total += Math.abs(v);
        }
        return total;
    }
  
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String a = in.next();
        String b = in.next();
        System.out.println(numberNeeded(a, b));
    }
}

def number_needed(str1, str2):
    
    dict_chars = dict()
    
    for char in str1:
        if char in dict_chars:
            dict_chars[char] += 1
        else:
            dict_chars[char] = 1
    for char in str2:
        if char in dict_chars:
            dict_chars[char] -= 1
        else:
            dict_chars[char] = -1
    
    sum_diff = 0
    
    for char in dict_chars.keys():
        sum_diff += abs(dict_chars[char])
        
    return sum_diff
    
a = input().strip()
b = input().strip()

print(number_needed(a, b))