Problem:
Score : 100 points

Problem Statement

A Hitachi string is a concatenation of one or more copies of the string hi.

For example, hi and hihi are Hitachi strings, while ha and hii are not.

Given a string S, determine whether S is a Hitachi string.

Constraints

The length of S is between 1 and 10 (inclusive).

S is a string consisting of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If S is a Hitachi string, print Yes; otherwise, print No.

Sample Input 1

hihi

Sample Output 1

Yes

hihi is the concatenation of two copies of hi, so it is a Hitachi string.

Sample Input 2

hi

Sample Output 2

Yes

Sample Input 3

ha

Sample Output 3

No

Solution in Common Lisp (SBCL 1.1.14) (judge verdict: Accepted)

(format t "~:[No~;Yes~]~%"
	(let* ((s (read-line))
	       (l (length s)))
	  (if (oddp l)
	      nil
	      (loop for i upto (- l 2) by 2
		 always (equal "hi" (subseq s i (+ i 2)))))))