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 Scala (2.11.7) (judge verdict: Accepted)

object Main extends App {
  val s =  scala.io.StdIn.readLine()
  if(s.length % 2 == 0) {
    var tempS = s
    var yesFlag = true
    while(tempS.length > 0) {
      if (tempS.substring(0, 2) != "hi") {
        yesFlag = false
        tempS = ""
      } else {
        if(tempS.length > 3) {
          tempS = tempS.substring(2)
        } else {
          tempS = ""
        }
      }
    }
    if (yesFlag) println("Yes") else println("No")
  } else {
    println("No")
  }

}