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)

str = gets
len = str.length
key = 0
if	len%2 == 1
	key = 0
else
  	len /= 2
  	len.times do |i|
    	if str[2*i] == "h" && str[2*i+1] == "i"
       	  key = 1
        else
          key = 0
          break
        end
    end
end

if key == 1
	puts "Yes"
else
	puts "No"
end