import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        String s=scanner.next();
        String t=scanner.next();

        int diffCount=0;
        for (int i = 0; i < s.length() && i<t.length(); i++) {
            if(s.charAt(i) == t.charAt(i))
                diffCount++;
        }

        System.out.println(diffCount);
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz