Ingenieria

Simply Syntax 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 syntaxof 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 thesyntactical 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 onlycharacters 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 correctsentence, 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 syntacticalcorrectness 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 anumber 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 isterminated 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 consistsof 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 isfollowed 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