import java.util.*;


public class Main{
    public static void main(String[] args) throws Exception{
        
        Scanner sc = new Scanner(System.in);
        
        String s = sc.next();
        String t = sc.next();

        if(t.startsWith(s)){
            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