import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

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

        if (T.startsWith(S) && T.length() == S.length() + 1) {
            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.next();
        String T = scanner.next();

        if (T.startsWith(S) && T.length() == S.length() + 1) {
            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.next();
        String T = scanner.next();

        if (T.startsWith(S) && T.length() == S.length() + 1) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } main {
        Scanner scanner = new Scanner(System.in);

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

        if (T.startsWith(S) && T.length() == S.length() + 1) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) String S = scanner.next(); S scanner.next() scanner.next scanner String T = scanner.next(); T scanner.next() scanner.next scanner if (T.startsWith(S) && T.length() == S.length() + 1) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } T.startsWith(S) && T.length() == S.length() + 1 T.startsWith(S) T.startsWith T S T.length() == S.length() + 1 T.length() T.length T S.length() + 1 S.length() S.length S 1 {
            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.next();
        String T = scanner.next();

        if (T.startsWith(S) && T.length() == S.length() + 1) {
            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.next();
        String T = scanner.next();

        if (T.startsWith(S) && T.length() == S.length() + 1) {
            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.next();
        String T = scanner.next();

        if (T.startsWith(S) && T.length() == S.length() + 1) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}
