import java.util.Scanner;

public class Main {
    public static void main(final String args[]) {
        Scanner scan = new Scanner(System.in);
        String S = scan.next();
        String T = scan.next();
        for(int i = 0;i < S.length();i++){
            if(S.charAt(i) != T.charAt(i)){
                System.out.println("No");
                break;
            }else if((i == S.length() - 1)&&(S.length() == T.length() -1 )){
                System.out.println("Yes");
            }else if(S.length() == T.length()){
                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