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)

a = gets.chomp.split("")
flag = 0
a.length.times do |k|
  if (k - 1) % 2 == 0
    if a[k - 1] != "h"
      flag = 1
    end
  else
    if a[k - 1] != "i"
      flag = 1
    end
  end
end

if a.length == 1
  flag = 1
end

if flag == 0
  puts "Yes"
else
  puts "No"
end