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;
#define LL long long
 
int main()
{
  string s;
  cin>>s;
  set<string>st;
  for(int i=0;i<s.size();i+=2){
      string ss=s.substr(i,2);
      st.insert(ss);
  }
  
  string f;
  for(auto x:st) f=x;
  if(st.size()==1 and f=="hi") cout<<"Yes"<<"\n";
  else cout<<"No"<<"\n";
    return 0; 
}