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: Wrong Answer)

<?php
$input = file_get_contents('php://stdin');

if(strlen($input)%2!=0){
    echo "No" . PHP_EOL;
    exit();
}
$length = (int)floor(strlen($input)/2);
for($i=0;$i<$length;$i++){
    $output = substr($input, $i*2, 2);
    if($output!=="hi"){
        echo "No" . PHP_EOL;
        exit();
    }
}
echo "Yes" . PHP_EOL;

?>