A11170. Alex and broken contest
编程题
普及/提高-
知识点
题目描述
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.
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.
输入格式
The only line contains string from lowercase and uppercase letters and "\_" symbols of length, not more than $100$ — the name of the problem.
输出格式
Print "YES", if problem is from this contest, and "NO" otherwise.
输入输出样例
输入 #1
Alex_and_broken_contest
输出 #1
NO
输入 #2
NikitaAndString
输出 #2
YES
输入 #3
Danil_and_Olya
输出 #3
NO