import java.io.*;        


public class test {

   public static void main(String[] args) throws FileNotFoundException, IOException {
        PrintWriter out;
        try (BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream("input.txt"),"UTF-8"))) {
            String tempNumber;
            String answer = "нет";
            while ((tempNumber = in.readLine()) != null) {
               try{
                if(Integer.parseInt(tempNumber)==7){
                    answer = "да";
                }
               }catch(Exception e){}
            }               
            out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(new FileOutputStream("output.txt", false),"cp1251")));
            out.print(answer);
            
        }
        out.flush();
        out.close();
    }