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: Wrong Answer)

#pragma GCC optimize(2)
#include<bits/stdc++.h>
using namespace std;
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define x first
#define y second
typedef long long LL;
typedef pair<int, int> PII;
bool suc = true;
string s;

int main(){
	ios::sync_with_stdio(false); cin.tie(nullptr);
	cin >> s;
	if(s.size() & 1) suc = false;
	else{
		for(int i = 0; i < sz(s); i += 2){
			if(s[i] != 'h') suc = false;
		}
		for(int i = 1; i< sz(s); i += 2){
			if(s[i] != 'i') suc = false;
		}
	}
	if(suc) cout << "YES\n";
	else cout << "NO\n";
	return 0;
}