#include<bits/stdc++.h>
using namespace std;
int main(){
	string s;
	cin>>s;
	if(s.size()%2){
		cout<<"No"<<endl;
		return 0;
	}
	for(int i=0;i<s.size();i+=2){
		if(s[i]!='h'||s[i+1]!='i'){
			cout<<"No"<<endl;
			return 0;
		}
	}
	cout<<"Yes"<<endl;
	return 0;
}