import java.util.*;

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

        int sLen = S.length();
        int tLen = T.length();
        if (S.equals(T.substring(0, tLen-1)))
            System.out.println("Yes");
        else
            System.out.println("No");
    }
} import java.util.*; util.* java class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String S = sc.next();
        String T = sc.next();

        int sLen = S.length();
        int tLen = T.length();
        if (S.equals(T.substring(0, tLen-1)))
            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.next();
        String T = sc.next();

        int sLen = S.length();
        int tLen = T.length();
        if (S.equals(T.substring(0, tLen-1)))
            System.out.println("Yes");
        else
            System.out.println("No");
    } main {
        Scanner sc = new Scanner(System.in);
        String S = sc.next();
        String T = sc.next();

        int sLen = S.length();
        int tLen = T.length();
        if (S.equals(T.substring(0, tLen-1)))
            System.out.println("Yes");
        else
            System.out.println("No");
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String S = sc.next(); S sc.next() sc.next sc String T = sc.next(); T sc.next() sc.next sc int sLen = S.length(); sLen S.length() S.length S int tLen = T.length(); tLen T.length() T.length T if (S.equals(T.substring(0, tLen-1)))
            System.out.println("Yes");
        else
            System.out.println("No"); S.equals(T.substring(0, tLen-1)) S.equals S T.substring(0, tLen-1) T.substring T 0 tLen-1 tLen 1 System.out.println("Yes") System.out.println System.out System System.out "Yes" System.out.println("No") System.out.println System.out System System.out "No" String[] args args
import java.util.*;

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

        int sLen = S.length();
        int tLen = T.length();
        if (S.equals(T.substring(0, tLen-1)))
            System.out.println("Yes");
        else
            System.out.println("No");
    }
}
