
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
	
	Scanner sc = new Scanner(System.in);
	String S = sc.nextLine();
	String T = sc.nextLine();
	int ans = 0;
	
	
	
	
	for(int i=0; i<3; i++)
	{
		if(S.charAt(i) == T.charAt(i))
		{
			ans++;
		}
	}
	System.out.println(ans);
	
	}
	
}
