import java.util.*;
public class Main {
  public static void main(String[] args) {
    Scanner console = new Scanner(System.in);
    String word1 = console.next();
    String word2 = console.next();
    String end = word2.substring(0, word1.length());
    if (word1.compareTo(end) == 0) {
      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