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)

#pragma GCC optimize("O3")   //
#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define per(i, b, a) for(int i = b - 1; i >= a; i--)
#define trav(a, x) for(auto& a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef long double ld;

unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
std::mt19937 eng(seed);

uniform_int_distribution<> DD(0, (1ll << 31));

ll random2(){
    return (ll(DD(eng))*(1ll << 31) + ll(DD(eng))) & ((1ll << 62ll)-1);
}

ll n,m,k,q,T;

const ll big = 1000000007;
const ll big2 = 1000000009;
const ll mod =  998244353;

const int MAXN = 500001;


int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    //freopen("input.txt","r",stdin);
    //freopen("autput.txt","w",stdout);
    ll a,b,c,d,e;
    string s;

    cin >> s;
    n = s.length();
    if(n%2 == 1){
        cout << "No\n";
        return 0;
    }
    for(int c1 = 0; c1 < n; c1 += 2){
        if(s[c1] != 'h' || s[c1+1] != 'i'){
            cout << "No\n";
            return 0;
        }
    }
    cout << "Yes\n";

    return 0;
}