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 PHP (5.6.30) (judge verdict: Wrong Answer)

<?php
$q = str_replace("\r\n","",fgets(STDIN));
$len = strlen($q);
$next = $q;
if(strlen($q) == 1){
    printf("No");
    exit;
}
for($j=0; $j<$len-1; $j++){
    $buf = $next;
    if(substr($buf,0,2) != "hi"){
        printf("No\r\n");
        exit;
    }
    if (strlen($buf) == 2){
        printf("Yes\r\n");
        exit;
    }
    //printf($buf."]\n");
    if ($buf[2] != 'h'){
        printf("No\r\n");
        exit;
    }
    $next = substr($buf,2);


}