import java.util.StringJoiner;
import java.util.Scanner;

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

String line2 = sc.nextLine();
String column[] = line2.split("");
String addword = column[line2.length() -1];
String newID = String.join("" , line , addword);

if(line2.equals(newID)){
  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