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: Wrong Answer)

// A Dynamic Programming based 
// C# program to find minimum 
// number operations to 
// convert str1 to str2 
using System;
using System.Collections.Generic;
using System.Linq;
class GFG
{
    public static void Main()
    {
        var input = Console.ReadLine();
        HitachiString(input);
    }

    static void HitachiString(string s)
    {
        if(s.Length%2!=0)
        {
            Console.Write("No");
            return;
        }

        if (s.Length == 2)
        {
            if (s[0] == 'h' && s[1] == 'i')
            {
                Console.Write("Yes");
                return;
            }
            else
            {
                Console.Write("No");
                return;
            }
        }
        for (int i = 2; i < s.Length; i++)
        {

            if (s[i] != s[i - 2])
            {
                Console.Write("No");
                break;
            }

        }

        Console.Write("Yes");

    }





}