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 <bits/stdc++.h>
#define fr(i,n) for(int i=0;i<n;i++)
#define pb push_back
typedef long long ll;
typedef long double la;
using namespace std;
 
int main(){
    string s;
    int j=0,k;
    cin >> s;
    fr(i,s.size()){
        if(s[i] == 'h'){
            if(i != 0){
                if(s[--i] != 'i'){
                    j = 0;
                }
            }
            k = i + 2;
            if(s[++i] == 'i'){
                if(s.size() != 3){
                if(s[k] != 'i'){
                    j = 1;
                }
                }  
            }
        }
    }
    if(j==0){
        cout << "No" << endl;
    }else{
        cout << "Yes" << endl;
    }
    //cout << j << endl;
}