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)

# frozen_string_literal: true

def factor(n)
  return [1] if n == 1

  `factor #{n}|sed -r 's/[0-9]+://g'|tr ' ' '\n'|sort -n`.split.map(&:to_i)
end

# Example: factors(100) => {2=>2, 5=>2}
def factors_and_num(n)
  factors = factor(n)
  ret = Hash.new(0)
  factors.each do |i|
    ret[i] += 1
  end
  ret
end

def uniq_factor(n)
  `factor #{n}|sed -r 's/[0-9]+://g'|tr ' ' '\n'|sort -n|uniq`.split.map(&:to_i)
end

if gets.scan(/hi/).count != 0
  puts 'Yes'
else
  puts 'No'
end