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.
The only line contains string from lowercase and uppercase letters and "_" symbols of length, not more than 100 — the name of the problem.
none
Alex_and_broken_contest
NO
NikitaAndString
YES
Danil_and_Olya
NO
Slava____and_the_game
YES
Olya_and_energy_drinks
YES
Danil_and_part_time_job
YES
Ann_and_books
YES
Olya
YES
Nikita
YES
Slava
YES
Vanya
NO
I_dont_know_what_to_write_here
NO
danil_and_work
NO
Ann
YES
Batman_Nananananananan_Batman
NO
Olya_Nikita_Ann_Slava_Danil
NO
its_me_Mario
NO
A
NO
Wake_up_Neo
NO
Hardest_problem_ever
NO
Nikita_Nikita
NO
____________________________________________________________________________________________________
NO
Nikitb
NO
Unn
NO
oLya_adn_smth
NO
FloorISLava
NO
ann
NO
aa
NO
AAnnnnn
YES
AnnAnn
NO
Annn
YES
Dilzhan
NO
Danilaaa
YES
AndAnn
YES
OlyaAnnAnn
NO
DanilDanilOlya
NO
DDanil
YES
AnnAnnDanil
NO
And_Danil
YES
abcddddDanil
YES
DanilOlyaOlya
NO
Nikitaaa
YES
aaabbba
NO
Ann_Ann_Danil
NO
Danil_Danil_Nikita
NO
AlexaaaaaaBBBBBOlyaDDDDD
YES
IloveDaniland
YES
AnAnn
YES
Danil_Danil_Olya
NO
DanilDanilSlava
NO
DanilDanil
NO
OlyOlya
YES
NikitaNikitb
YES
ababaca
NO
AnnNikitaNikitaNikitaNikita__good_luck
NO
import re
a = ["Danil", "Olya", "Slava", "Ann", "Nikita"]
pr = input()
qw = re.findall('([A-Z][^A-Z]*)', pr)
if len(pr) == 1:
    pr = pr.split('_')
count = 0

for i in a:
    for j in qw:
        if i == j:
            count += 1

if count == 1:
    print("YES")
else:
    print("NO")
	 		 		 	 						     			 		 	