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)

#include <algorithm>
#include <iostream>
#include <vector>
#include <queue>
#include <set>
#include <string>
#include <map>
#include <cmath>
#include <cstring>

#define fi first
#define se second
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define rrep(i,n) for (int i = 1; i < (n); ++i)
#define drep(i,n) for (int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define all(x) (x).begin(), (x).end()
#define maxs(x,y) (x = max(x,y))
#define mins(x,y) (x = min(x,y))
#define pb push_back
#define sz(x) (int)(x).size()
#define PQ(T) priority_queue<T, v(T), greater<T> >

using namespace std;
using ll = long long;
using uint = unsigned;
using ull = unsigned long long;
using P = pair<int,int>;

const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;

const int mod = 1000000007;

int main() {
    string s; cin >> s;
    if (s.size()%2!=0) cout << "No" << endl;
    
    string ans = "Yes";
    for (int i = 0; i<s.size(); i=i+2) {
        string tmp = s.substr(i,2);
        if (tmp != "hi") ans = "No";
    }
    cout << ans << endl;
    return 0;
}