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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;

namespace A___Hitachi_String
{
    class Program
    {
        static void Main (string[] args)
        {
            var s = Console.ReadLine ();
            if (s.Length % 2 == 1)
            {
                Console.WriteLine ("No");
                return;
            }
            for (var i = 1; i < s.Length; i+=2)
            {
                if (s[i - 1] != 'h' || s[i] != 'i')
                {
                    Console.WriteLine ("No");
                    return;
                }
            }
            Console.WriteLine ("Yes");
        }
    }
}