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();

		if (T.matches(S + "[a-z]")) {
			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 sc = new Scanner(System.in);
		String S = sc.nextLine();
		String T = sc.nextLine();

		if (T.matches(S + "[a-z]")) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}

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

		Scanner sc = new Scanner(System.in);
		String S = sc.nextLine();
		String T = sc.nextLine();

		if (T.matches(S + "[a-z]")) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	} main {

		Scanner sc = new Scanner(System.in);
		String S = sc.nextLine();
		String T = sc.nextLine();

		if (T.matches(S + "[a-z]")) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String S = sc.nextLine(); S sc.nextLine() sc.nextLine sc String T = sc.nextLine(); T sc.nextLine() sc.nextLine sc if (T.matches(S + "[a-z]")) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		} T.matches(S + "[a-z]") T.matches T S + "[a-z]" S "[a-z]" {
			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 sc = new Scanner(System.in);
		String S = sc.nextLine();
		String T = sc.nextLine();

		if (T.matches(S + "[a-z]")) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}

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

		Scanner sc = new Scanner(System.in);
		String S = sc.nextLine();
		String T = sc.nextLine();

		if (T.matches(S + "[a-z]")) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}

} Main
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();

		if (T.matches(S + "[a-z]")) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}

}
