StringBuilder+char[]

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        StringBuilder sb=new StringBuilder();
        sb.append(sc.nextLine());
        String str=sc.nextLine();
        char[] ch=str.toCharArray();
        for(int i=0;i<str.length();i++)
        {
            int index=sb.indexOf(String.valueOf(ch[i]));
            if(index!=-1)
            {
                sb.delete(0,index+1);
                System.out.println(sb);
            }
            else
            {
                System.out.println(i);
                break;
            }
        }
    }
}