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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
 
public class Main {

    public static void main(String[] args) {
 
        Scanner sc = new Scanner(System.in);
        String S = sc.next();

        boolean ok = true;

        for (int i = 0; i < S.length(); i++) {
            char c = S.charAt(i);
            if (i % 2 == 0) {
                if (c != 'h') ok = false;
            } else {
                if (c != 'i') ok = false;
            }
        }
        if (ok) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

    }

}