import java.util.Scanner;

class Main{
	public static void main(String[] args){
      Scanner sc = new Scanner(System.in);
      
 		String S = sc.next();
      	String T = sc.next();
      
      	int a = S.length();
       	String b = T.substring(0,a);
 
      if(S.equals(b)){
      	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