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 Ruby (2.3.3) (judge verdict: Wrong Answer)

def judge(s)
  s.size.times do |i|
    return false unless ((s[i] == 'h') || (s[i] == 'i'))

    if (i % 2) == 0 then
      return false unless s[i] == 'h'
    else
      return false unless s[i] == 'i'
    end
  end
 
  return true
end
 
s = gets.chomp
puts (judge(s) ? 'Yes' : 'No')