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: Runtime Error)

s = input()
s_len = len(s)
if s_len % 2:
  print("No")
else:
  prev = 0
  count = 0
  for i in range(1, (s_len//2)+1):
    if [prev:i*2] != "hi":
      print("No")
      break
    else:
      count += 1
      prev = i * 2
  if count == s_len:
    print("Yes")