import java.util.Scanner;
import java.util.List;
import java.util.ArrayList;

public class Main {
  public static void main(String[] args ){

    Scanner sc = new Scanner(System.in);

    String S = sc.next();
    String T = sc.next();

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

      char s = S.charAt(i);
      char t = T.charAt(i);
      cnt += s == t ? 1 : 0;
    }

    System.out.println(cnt);
  }
}

/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