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
#----------FASTIOSTART-----------#

from __future__ import division, print_function
import os
import sys
from io import BytesIO, IOBase
if sys.version_info[0] < 3:
	from __builtin__ import xrange as range
	from future_builtins import ascii, filter, hex, map, oct, zip
BUFSIZE = 8192
class FastIO(IOBase):
	newlines = 0
	def __init__(self, file):
		self._fd = file.fileno()
		self.buffer = BytesIO()
		self.writable = "x" in file.mode or "r" not in file.mode
		self.write = self.buffer.write if self.writable else None
	def read(self):
		while True:
			b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
			if not b:
				break
			ptr = self.buffer.tell()
			self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
		self.newlines = 0
		return self.buffer.read()
	def readline(self):
		while self.newlines == 0:
			b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
			self.newlines = b.count(b"\n") + (not b)
			ptr = self.buffer.tell()
			self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
		self.newlines -= 1
		return self.buffer.readline()
	def flush(self):
		if self.writable:
			os.write(self._fd, self.buffer.getvalue())
			self.buffer.truncate(0), self.buffer.seek(0)
class IOWrapper(IOBase):
	def __init__(self, file):
		self.buffer = FastIO(file)
		self.flush = self.buffer.flush
		self.writable = self.buffer.writable
		self.write = lambda s: self.buffer.write(s.encode("ascii"))
		self.read = lambda: self.buffer.read().decode("ascii")
		self.readline = lambda: self.buffer.readline().decode("ascii")
def print(*args, **kwargs):
	sep, file = kwargs.pop("sep", " "), kwargs.pop("file", sys.stdout)
	at_start = True
	for x in args:
		if not at_start:
			file.write(sep)
		file.write(str(x))
		at_start = False
	file.write(kwargs.pop("end", "\n"))
	if kwargs.pop("flush", False):
		file.flush()
if sys.version_info[0] < 3:
	sys.stdin, sys.stdout = FastIO(sys.stdin), FastIO(sys.stdout)
else:
	sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")

#----------FASTIOFINISH----------#

import collections,itertools,statistics,math
from collections import *
from itertools import * 
from statistics import *
from math import *
mod=int(1e9+7)
imin=-2147483648;
imax=2147483647;
true=True
false=False
none=None
inp = lambda : input()
I   = lambda : int(inp())
M   = lambda : map(int,inp().split())
L   = lambda : list(M())
Yes = lambda : print("Yes")
No  = lambda : print("No")

YES = lambda : print("YES")
NO  = lambda : print("NO")
def IO():
	sys.stdin = open('input.txt', 'r')
	sys.stdout = open('output.txt', 'w')

#----------UserCodeStart-----------#

def kabraji_ka_totka():
	# totka hai dosto !
	#IO()
	# "Danil", "Olya", "Slava", "Ann" and "Nikita".
	s=inp()
	"""
	cnts=[]
	cnts.append(s.count("Danil"))
	cnts.append(s.count("Olya"))
	cnts.append(s.count("Slava"))
	cnts.append(s.count("Ann"))
	cnts.append(s.count("Nikita"))

	if cnts.count(1) == 1:
		YES()
	else:
		NO()
	"""
	cnt=0;
	cnt+=s.count("Danil")+s.count("Olya")+s.count("Slava")+s.count("Ann")+s.count("Nikita")
	if cnt==1:
		YES()
	else:
		NO()
#----------UserCodeFinish----------#

if __name__=="__main__":
	kabraji_ka_totka()
