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;
using System.Linq;
using System.Text;
using System.Collections.Generic;

class Program
{
	static void Main(string[] args)
	{
		//読み込む
		string S = Console.ReadLine();
		if(S == "hi" || S == "hihi" || S == "hihihi" ||
    S == "hihihihi" || S == "hihihihihi"){
        Console.WriteLine("Yes");
    }else{
        Console.WriteLine("No");
    }

	}
}