class Main {
	public static void main(String[] args) {
      	java.util.Scanner input = new java.util.Scanner(System.in);
      	String S = input.nextLine();
      	String T = input.nextLine();
    	 new Main().solve(S, T);
    }
  	private void solve(String s, String t) {
      if(s.length() >= t.length())
        System.out.print("No");
    	 if(s.equals(t.substring(0, s.length())))
          System.out.print("Yes");
        else
          System.out.print("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