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: Wrong Answer)

S = input()
if len(S) % 2 == 1:
    print('No')
    exit()
else:
    if S[0] != "h":
        print('No')
        exit()
    for i in range(len(S)-1):
        flag = True
        if S[i] == "i":
            if S[i-1] != "h":
                flag = False
        elif S[i] == "h":
            if S[i-1] != "i":
                flag = False
        else:
            flag = False
if flag:
    print('Yes')
else:
    print('No')