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

namespace CSharpSample01
{


	class Program
	{
		static void Main(string[] args)
		{
			var S = Console.ReadLine();
			var flag = true;

			for(int i = 0; i < S.Length; i++)
			{
				if(i % 2 == 0)
				{
					if(S[i] != 'h')
					{
						flag = false;
						break;
					}
				}
				else
				{
					if (S[i] != 'i')
					{
						flag = false;
						break;
					}

				}
			}

			if (S.Length % 2 == 1)
			{
				flag = false;
			}

			if (flag)
			{
				Console.WriteLine("Yes");
			}
			else
			{
				Console.WriteLine("No");
			}

		}
	}
}