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));
    }
}