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> 
#include <chrono>
using namespace std;
 
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}
 
 
//typedef
//------------------------------------------
typedef pair<int, int> PII;
typedef long long LL;
typedef pair<LL, LL> PLL;
 
//container util
//------------------------------------------
#define PB emplace_back
#define MP make_pair 
#define SZ(a) int((a).size())
//repetition
//------------------------------------------
#define FOR(i,a,b) for(LL i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define SORT(c) sort((c).begin(),(c).end())
#define ALL(a)  (a).begin(),(a).end()
//constant
//--------------------------------------------
//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

const int MAX_N=2e5+3;


const unsigned long long B=1e12+7;

LL MOD=1000000007;
int main(){
    string S;cin>>S;
    bool flag=true;
    if(SZ(S)%2==1)flag=false;
    for(int i=0;i<SZ(S)-1;i+=2){
        if(!(S[i]=='h'&&S[i+1]=='i'))flag=false;
    }
    if(flag)cout<<"Yes"<<endl;
    else cout<<"No"<<endl;
    return 0;
}