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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

function Main(input) {
  input = String(input);
  
  if(input.length>10){console.log("No");return;}
  
  if((input.length)%2===1){console.log("No");return;}
  
  var ret = "Yes";
  for(i=0;i<input.length;i=i+2) {
//    console.log("%i",i);
    if (input.indexOf("hi",i)!=i){ret="No";break;}
  }
  console.log(ret);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));