import java.io.BufferedReader;
import java.io.InputStreamReader;

class Main {
	public static void main(String args[])throws Exception
	{
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		String s=br.readLine();
		String t=br.readLine();
		int len=t.length();
		if(s.contentEquals(t.substring(0,len-1)))
			System.out.println("Yes");
		else
			System.out.println("No");
	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io class Main {
	public static void main(String args[])throws Exception
	{
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		String s=br.readLine();
		String t=br.readLine();
		int len=t.length();
		if(s.contentEquals(t.substring(0,len-1)))
			System.out.println("Yes");
		else
			System.out.println("No");
	}
} Main public static void main(String args[])throws Exception
	{
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		String s=br.readLine();
		String t=br.readLine();
		int len=t.length();
		if(s.contentEquals(t.substring(0,len-1)))
			System.out.println("Yes");
		else
			System.out.println("No");
	} main {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		String s=br.readLine();
		String t=br.readLine();
		int len=t.length();
		if(s.contentEquals(t.substring(0,len-1)))
			System.out.println("Yes");
		else
			System.out.println("No");
	} BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) String s=br.readLine(); s br.readLine() br.readLine br String t=br.readLine(); t br.readLine() br.readLine br int len=t.length(); len t.length() t.length t if(s.contentEquals(t.substring(0,len-1)))
			System.out.println("Yes");
		else
			System.out.println("No"); s.contentEquals(t.substring(0,len-1)) s.contentEquals s t.substring(0,len-1) t.substring t 0 len-1 len 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.io.BufferedReader;
import java.io.InputStreamReader;

class Main {
	public static void main(String args[])throws Exception
	{
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		String s=br.readLine();
		String t=br.readLine();
		int len=t.length();
		if(s.contentEquals(t.substring(0,len-1)))
			System.out.println("Yes");
		else
			System.out.println("No");
	}
}
