One day Alex was creating a contest about his friends, but accidentally deleted it. Fortunately, all the problems were saved, but now he needs to find them among other problems.

But there are too many problems, to do it manually. Alex asks you to write a program, which will determine if a problem is from this contest by its name.

It is known, that problem is from this contest if and only if its name contains one of Alex's friends' name exactly once. His friends' names are "Danil", "Olya", "Slava", "Ann" and "Nikita".

Names are case sensitive.

Input

The only line contains string from lowercase and uppercase letters and "_" symbols of length, not more than 100 — the name of the problem.

Output

Print "YES", if problem is from this contest, and "NO" otherwise.

Examples

Input

Alex_and_broken_contest


Output

NO

Input

NikitaAndString


Output

YES

Input

Danil_and_Olya


Output

NO
/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/*
 * @author Rohini Chandra
 */
import java.util.*;
import java.io.*;
public class rough{
    public static void main(String args[]) throws IOException{
       /*BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
       PrintWriter pw = new PrintWriter(System.out);*/
       //List<Integer> list = new ArrayList<>();
       //Map<Integer,Integer> map = new HashMap<>();
       //Set<Integer> set = new HashSet<>();
       Scanner sc = new Scanner(System.in);
       String str = sc.next();
       //List<String> list = Arrays.asList("Danil", "Olya", "Slava", "Ann" ,"Nikita");
       int cnt=0,in;
       StringBuilder sb = new StringBuilder(str);
       while(sb.length()!=0){
             if(str.contains("Danil")){
                cnt++;
                in = sb.indexOf("Danil");//prtl(sb);
                sb.delete(in, in+5);
                //sb.append("_", in, in+5);
                sb.insert(in, "-");
                str="";
                str += sb;
             }
             else if(str.contains("Olya")){
                cnt++;
                in = sb.indexOf("Olya");//prtl(sb);
                sb.delete(in, in+4);
                sb.insert(in, "-");
                str="";
                str += sb;
             }
             else if(str.contains("Slava")){
                cnt++;
                in = sb.indexOf("Slava");//prtl(sb);
                sb.delete(in, in+5);
                sb.insert(in, "-");
                str="";
                str += sb;
             }
             else if(str.contains("Ann")){
                cnt++;
                in = sb.indexOf("Ann");
                sb.delete(in, in+3);
                sb.insert(in, "-");
                //sb.append("_", in, in+1);
                str="";
                str += sb;//prtl(str);
             }
             else if(str.contains("Nikita")){
                cnt++;
                in = sb.indexOf("Nikita");//prtl(sb);
                sb.delete(in, in+6);
                sb.insert(in, "-");
                str="";
                str += sb;
             }
             else
                 break;
             if(cnt>1)
                 break;
             //prtl(str);
       }
       if(cnt==1)
           prtl("YES");
       else
           prtl("NO");
    }
                                        //******** PRINT ********//
    static void prt(int a){
       System.out.print(a);
    }
                                       //******** PRINTLN ********//
    static void prtl(String b){
       System.out.println(b); 
    }         
                                       //******** FACTORIAL ********//
    static int fact(int n){
       if(n==1)
          return 1;
       else
          return n*fact(n-1);
    }
                                       //******** OCCURRENCE ********//
    static Map<String,Integer> ocr(String str[]){
           Map<String,Integer> map = new HashMap<>();
           for(int i=0; i<str.length; i++){
           if(!map.containsKey(str[i]))
              map.put(str[i], 1);
           else
              map.put(str[i], map.get(str[i])+1);
           }
           return map;
    }
                                        //******** PRIME OR NOT ********//
    static boolean isprime(long num){
        if(num<=1)
            return false;
        else if(num<=3)
            return true;
        else if(num%2==0 || num%3==0)
            return false;
        else{
            for(int i=5; i*i<=num; i+=6){
                if(num%i==0 || num%(i+2)==0)
                   return false; 
            }
            return true;
        }
    }
                                       //******** GCD ************//
    static long gcd(long a, long b){
         if(b==0)
            return a;
         else if(a==0)
            return b;  
         else if(a>b)
            gcd(a%b,b);
         else if(a<b)
            gcd(a,b%a);
         else if(a==b)
            return a;
         return 0;
    }
}
