import java.util.*;

public class Slotgame {

public static int slotScore(String original, String guess) {

// Write your code here.

if (guess.length() == 0 || original.length() == 0) {

return 0;

}

int count = 0;

Set<Character> originalChars = new HashSet<>(); // To track used characters

Set<Character> guessChars = new HashSet<>();

for (int i = 0; i < original.length(); i++) {

if (original.charAt(i) == guess.charAt(i)) {

count += 2;

} else {

originalChars.add(original.charAt(i));

guessChars.add(guess.charAt(i));

}

}

for (char c : guessChars) {

if (originalChars.contains(c)) {

count++;

originalChars.remove(c); // Remove the character from originalChars to avoid double counting

}

}

return count;

}

public static void main(String[] args) {

Scanner sc = new Scanner(System.in); // System.in is a standard input stream

String original = sc.next();

String guess = sc.next();

sc.close();

int ans = slotScore(original, guess);

System.out.println(ans);

}

}