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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php
//error_reporting(0);
$S = trim(fgets(STDIN));
//list($A,$B) = explode(" ",trim(fgets(STDIN)));
//$a[] = array_map('intval',explode(" ",trim(fgets(STDIN))));

if (str_replace("hi","",$S)=="") {
  printf("Yes\n");
}
else {
  printf("No\n");
}