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.Scanner;

public class Main
{
	public static void main(String[] args)
	{
		Scanner scan = new Scanner(System.in);
		String str = scan.nextLine();
		char[] c = str.toCharArray();
		String ans = "Yes";

		for (int i=0; i < str.length(); i++) {
			if (i % 2 == 1) {
				if (c[i] != 'i') {
					ans = "No";
					break;
				}
			}
			if (i % 2 == 0) {
				if (c[i] != 'h' ) {
					ans = "No";
					break;
				}
			}
		}
		scan.close();
		System.out.println(ans);
	}
}