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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <string>
#include <list>
#define REP(i,n) for(int i=0;i<(n);++i)
using namespace std;
typedef long long LL;

int main(){
  string S;
  cin >> S;
  int len = S.size();
  int ret;
  if(len % 2 == 0) {
    ret = true;
    for(int i=0; i<len; i+=2) {
      if(S[i] != 'h' || S[i+1] != 'i') {
        ret = false;
      }
    }
  } else {
    ret = false;
  }
  cout << (ret ? "Yes" : "No") << endl;
}