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)

#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define MOD 1000000007
using namespace std;
using ll = long long;
int main()
{
    string s;
    cin >> s;
    if(s.size() % 2 == 1)
    {
        cout << "No\n";
        return 0;
    }
    for(int i = 0;i < s.size();i++)
    {
        if(!(i % 2 == 0 && s[i] == 'h' || i % 2 == 1 && s[i] == 'i'))
        {
            cout << "No\n";
            return 0;
        }
    }
    cout << "Yes\n";
    
    return 0;
}