import java.util.Scanner;

public class Main {

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

        if (s.length() + 1 == t.length() && t.substring(0, t.length() - 1).equals(s)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {

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

        if (s.length() + 1 == t.length() && t.substring(0, t.length() - 1).equals(s)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String s = scanner.nextLine();
        String t = scanner.nextLine();

        if (s.length() + 1 == t.length() && t.substring(0, t.length() - 1).equals(s)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } main {
        Scanner scanner = new Scanner(System.in);
        String s = scanner.nextLine();
        String t = scanner.nextLine();

        if (s.length() + 1 == t.length() && t.substring(0, t.length() - 1).equals(s)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) String s = scanner.nextLine(); s scanner.nextLine() scanner.nextLine scanner String t = scanner.nextLine(); t scanner.nextLine() scanner.nextLine scanner if (s.length() + 1 == t.length() && t.substring(0, t.length() - 1).equals(s)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } s.length() + 1 == t.length() && t.substring(0, t.length() - 1).equals(s) s.length() + 1 == t.length() s.length() + 1 s.length() s.length s 1 t.length() t.length t t.substring(0, t.length() - 1).equals(s) t.substring(0, t.length() - 1).equals t.substring(0, t.length() - 1) t.substring t 0 t.length() - 1 t.length() t.length t 1 s {
            System.out.println("Yes");
        } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
            System.out.println("No");
        } System.out.println("No") System.out.println System.out System System.out "No" String[] args args public class Main {

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

        if (s.length() + 1 == t.length() && t.substring(0, t.length() - 1).equals(s)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} public class Main {

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

        if (s.length() + 1 == t.length() && t.substring(0, t.length() - 1).equals(s)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main
import java.util.Scanner;

public class Main {

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

        if (s.length() + 1 == t.length() && t.substring(0, t.length() - 1).equals(s)) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}