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 <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
  string S;
  cin >> S;

  if(S.size() % 2 == 1) {
    cout << "No" << endl;
    return 0;
  }

  for(int i = 0; i < S.size() / 2 + 1; i++) {
    if(i % 2 == 0) {
      if(S.at(i) != 'h') {
        cout << "No" << endl;
        return 0;
      }
    } else {
      if(S.at(i) != 'i') {
        cout << "No" << endl;
        return 0;
      }
    }
  }

  cout << "Yes" << endl;
}