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 Python (3.4.3) (judge verdict: Accepted)

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys

s=input()

l = len(s)

if (l % 2 != 0):
    print('No')
    sys.exit()

for i in range(len(s)):
    if (i % 2 == 0 and s[i] != 'h') or (i % 2 == 1 and s[i] != 'i'):
        print('No')
        sys.exit()

print('Yes')