Simply Syntax

Time Limit: 1000 ms Memory Limit: 10000 KiB

Problem Description

   In the land of Hedonia the official language is Hedonian. A Hedonian
   professor had noticed that many of her students still did not master
   the syntax of Hedonian well. Tired of correcting the many syntactical
   mistakes, she decided to challenge the students and asked them to
   write a program that could check the syntactical correctness of any
   sentence they wrote. Similar to the nature of Hedonians, the syntax of
   Hedonian is also pleasantly simple. Here are the rules:
   
   0. The only characters in the language are the characters p through z
   and N, C, D, E, and I.
   
   1. Every character from p through z is a correct sentence.
   
   2. If s is a correct sentence, then so is Ns.
   
   3. If s and t are correct sentences, then so are Cst, Dst, Est, and
   Ist.
   
   4. Rules 0. to 3. are the only rules to determine the syntactical
   correctness of a sentence.
   
   You are asked to write a program that checks if sentences satisfy the
   syntax rules given in Rule 0. - Rule 4.

Input

The input consists of a number of sentences consisting only of
   characters p through z and N, C, D, E, and I. Each sentence is ended
   by a new-line character. The collection of sentences is terminated by
   the end-of-file character. If necessary, you may assume that each
   sentence has at most 256 characters and at least 1 character.

Output

The output consists of the answers YES for each well-formed sentence
   and NO for each not-well-formed sentence. The answers are given in the
   same order as the sentences. Each answer is followed by a new-line
   character, and the list of answers is followed by an end-of-file
   character.

Sample Input

Cp
Isz
NIsz
Cqpq

Sample Output

NO
YES
YES
NO

Hint


Source