import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);

        //N K
        char[] ifs = s.nextLine().toCharArray();
        char[] acts = s.nextLine().toCharArray();

        int ct = 0;
        for (int i = 0; i < ifs.length; i++) {
            if (ifs[i] == acts[i]) ct++;
        }

        System.out.println(ct);
    }
}
/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