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 <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <cctype>
#include <climits>
#include <bitset>
#include <utility>
#include <cstring>
#include <numeric>
using namespace std;
typedef long double ld;
typedef long long int ll;
typedef unsigned long long int ull;
typedef vector<int> vi;
typedef vector<char> vc;
typedef vector<string> vs;
typedef vector<pair<int,int>> vpii;
typedef vector<vector<int>> vvi;
typedef vector<vector<char>> vvc;
typedef vector<vector<string>> vvs;
#define rep(i,n) for(int i=0;i<n;i++)
#define repll(i,n) for(long long int i=0;i<n;i++)
#define fin(ans) cout<<(ans)<<endl
#define P 1000000007
#define STI(s) atoi(s.c_str())//string to int
#define mp(p,q) make_pair(p,q)
#define Sort(a) sort(a.begin(),a.end())
template<class T> inline bool chmax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
const int INF = INT_MAX;
const long long LLINF = 1LL<<60;
template <typename T_char>
char ToUpper (char cX) { return toupper(cX); }
//g++ -std=c++1z temp.cpp
//./a.exe
ll digit(ll a){
    ll count = 0;
    for (ll i = 0; i < a; i++)
    {   if (a == 0)
        {
            break;
        }else
        {
            a = a/10;
            count++;
        }
    }
    return count;
}
//桁数のカウント
//pow(x,n) == x^n
//sum = accumulate(v.begin(),v.end(),0);
ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a;}
ll lcm(ll a, ll b) { return a / gcd(a,   b) * b;}



int main(void){ios::sync_with_stdio(false);cin.tie(0);
/////////////////////////////////////////////////////

string s;
cin >> s;

if(s.length() % 2 != 0){
    cout << "No" << endl;
    return 0;
}
for(int i = 0;i < s.length()-1;i += 2){
    if(s[i] == 'h' && s[i+1] == 'i') ;
    else{
        cout << "No" << endl;
        return 0;
    }
}

cout << "Yes" << endl;

//////////////////////////////////////////////////////
return 0;}