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
import java.io.*;
import java.util.*;
public class code {
	static PrintWriter pw;
	static boolean[] visit;
	static ArrayList<Pair>[] adj;
	static ArrayList<Integer> list;
	static long max=01;
	static void dfs(int i, long c) {
		visit[i]=true;
		max=Math.max(c, max);
		for(Pair p: adj[i]) {
			if(!visit[p.x-1]) {
				dfs(p.x-1, c+1l*p.y);
			}
		}
	}
	public static double dist(Pair a, Pair b) {
		return Math.sqrt((a.x-b.x)*(a.x-b.x)+ (a.y-b.y)*(a.y-b.y));
	}
	public static long gcf(long x, long y) {
		while(x%y!=0 && y%x!=0) {
			if(x>y)
				x%=y;
			else
				y%=x;
		}
		return x>y? y:x;
	}
	static long lcm(long x, long y) {
		return(x*y)/gcf(x,y);
	}
	static void swap(int[] arr,int i1,int i2) {
		int temp=arr[i1];
		arr[i1]=arr[i2];
		arr[i2]=temp;
	}
	public static void main(String[] args) throws Exception {
		Scanner sc= new Scanner(System.in);
		pw = new PrintWriter(System.out);
		boolean[] arr=new boolean[5];
		String s=sc.nextLine();
	       String[] arr2=new String[5];
	       arr[0]=s.contains("Danil");
	       arr[1]=s.contains("Olya");
	       arr[2]=s.contains("Slava");
	       arr[3]=s.contains("Ann");
	       arr[4]=s.contains("Nikita");
	       arr2[0]="Danil";
	       arr2[1]="Olya";
	       arr2[2]="Slava";
	       arr2[3]="Ann";
	       arr2[4]="Nikita";
	       int c=0;
	       int idx=-1;
	       for(int i=0; i<5; i++){
	           if(arr[i]){
	               c++;
	               idx=i;
	            }
	        }
	        if(c!=1){
	            pw.println("NO");
	        }else{
	            c=0;
	            for(int i=0; i<s.length(); i++){
	                if(s.charAt(i)==arr2[idx].charAt(0)){
	                    int tempi=i;
	                    boolean x=true;
	                    for(int j=0; j<arr2[idx].length() && x; j++,i++){
	                        if(s.charAt(i)!=arr2[idx].charAt(j))
	                            x=false;
	                    }
	                    if(x){
	                        c++;
	                        i--;
	                    }else{
	                       i=tempi;
	                    }
	                }
	            }
	            pw.println(c==1?"YES":"NO");
	        }
	        pw.close();
	}
	static class Scanner {
		StringTokenizer st;
		BufferedReader br;
 
		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}
 
		public Scanner(FileReader r) {
			br = new BufferedReader(r);
		}
 
		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}
 
		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}
 
		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}
 
		public String nextLine() throws IOException {
			return br.readLine();
		}
 
		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}
 
		public int[] nextArr(int n) throws IOException {
			int[] arr = new int[n];
			for (int i = 0; i < arr.length; i++)
				arr[i] = nextInt();
			return arr;
		}
		public Integer[] nextsort(int n) throws IOException{
			Integer[] arr=new Integer[n];
			for(int i=0; i<n; i++) 
				arr[i]=nextInt();
			return arr;
		}
		public boolean hasNext() throws IOException {
			return br.ready();
		}
	}
	static class Pair implements Comparable<Pair>{
		int x;
		int y;
		public Pair(int a, int b) {
			this.x=a;
			this.y=b;
		}
		public int compareTo(Pair other) {
			return this.y-other.y;
		}
	}
	static class Triple implements Comparable<Triple>{
		int x;
		int y;
		boolean d;
		public Triple(int a, int b, boolean t) {
			this.x=a;
			this.y=b;
			this.d=t;
		}
		public int compareTo(Triple other) {
			if(this.d && !other.d) {
				return 1;
			}else if(!this.d && other.d) {
				return -1;
			}else {
				return this.y-other.y;
			}
		}
	}
}