import java.util.*;
class Main {
 
    
    public static void main(String[] str)
    {
    	Scanner s=new Scanner(System.in);
    	String s1=s.next();
    	String s2=s.next();
    	int n=s2.length();
    	int i=0;
    	String res=s2.substring(i,n-1);
    	if(res.equals(s1))
    	{
    		System.out.println("Yes");
    	}
    	else
    	{
    		System.out.println("No");
    	}
   
    	
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz