Abdul has created a naming convention for places (countries, cities, streets, etc.). Words are composed of sections. There are three valid types of sections: A, B and C. The following elements are categorized into section A: ch, t, m, d, b, bd, r. The following elements are categorized into section B: a, e, i, oo. Finally, the following elements are categorized into section C: n, v, f. Valid words are composed of sections that follow strict placement rules. A word may start with either section A or B. A word must be at least 2 sections in length. A word cannot have two consecutive sections of the same type. A word must end with either section A or C. Section C can only end a word, and thus not exist anywhere else. A name consists of two or more words. The case is not relevant.

Given a name, check whether or not it is a valid name, according to the naming convention explained above. If it is valid, output valid otherwise, output invalid.

Input Specification

A single line with a name containing ~1 \le W \le 100~ words. Each word has ~1 \le L \le 200~ letters.

Output Specification

valid or invalid depending on whether the name given was a valid or invalid name according to Abdul's naming convention.

Sample Input 1

Abdoof Arif

Sample Output 1

valid

Sample Input 2

Abdul

Sample Output 2

invalid

Explanation for Sample Output 2

First of all, the word Abdul is not a valid word. Secondly, there is only 1 word in the name.