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;
using ld = long double;
using vl = vector<ll>;
template<class T> using vc = vector<T>;
template<class T> using vvc = vector<vector<T>>;

const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e16;
const ld EPS = 1e-11;
const ld PI = acos(-1.0L);
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define repr(i, n) for (ll i = (n)-1; i >= 0; i--)
#define repe(i, l, r) for (ll i = (l); i < (r); i++)
#define reper(i, l, r) for (ll i = (r)-1; i >= (l); i--)

template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

void init() {cin.tie(0);ios::sync_with_stdio(false);cout << fixed << setprecision(15);}
//--------------------------------------------------------------------------------//
ll n, a, b, c;
string s;
int main() {
    init();
    cin >> s;
    string t = "hi";
    if(s.size()%2==1){
        cout << "No" << endl;
        return 0;
    }
    bool isok = true;
    rep(i,s.size()/2){
        if (s.substr(2 * i, 2) != t) isok = false;
    }
    cout << (isok ? "Yes" : "No") << endl;
}