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)

require 'set'; require 'prime'
INF=Float::INFINITY; MOD=10**9+7
s = gets.chomp

if s.size.odd?
  puts 'No'
else
  s.size.times do |i|
    if i.even?
      if s[i] != 'h'
        puts 'No'
        exit
      end
    else
      if s[i] != 'i'
        puts 'No'
        exit
      end
    end
  end
end

puts 'Yes'