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)

using System;

class Program {
    static void Main (string[] args) {
        var inp = Console.ReadLine().Split(' ');
        string isHi = "No";

        bool ch_h = false;
        for(int i = 0;i < inp[0].Length;i++) {
            if(ch_h) {
                if(inp[0][i].Equals("i")) {
                    ch_h = false;
                    if(i == inp[0].Length - 1) {
                        isHi = "Yes";
                        break;
                    }
                    continue;
                }
            } else {
                if(inp[0][i].Equals("h")) {
                    ch_h = true;
                    continue;
                } else {
                    break;
                }
            }

        }

        Console.WriteLine(isHi);
    }
}