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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

main = do
  li <- getLine
  let ans = compute li
  putStrLn (if ans then "Yes" else "No")

compute :: String -> Bool
compute "" = False
compute cs = inner cs
  where
    inner ('h':'i':ss) = inner ss
    inner "" = True
    inner _ = False