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;
typedef long long ll;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vd = vector<double>;
using vvd = vector<vd>;

#define out(a) cout << a << endl
#define out1(a) cout << a
#define in(a) cin >> a
#define in2(a, b) cin >> a >> b
#define in3(a, b, c) cin >> a >> b >> c
#define rep(i, N) for (ll i = 0; i < (ll)N; i++)
#define rep1(i, N) for (ll i = 1; i <= (ll)N; i++)
#define repi(i, j, N) for (ll j = (ll)i + 1; j < (ll)N; j++)
#define all(v) v.begin(), v.end()

template <class T>
inline bool chmin(T &a, T b)
{
    if (a > b)
    {
        a = b;
        return true;
    }
    return false;
}
template <class T>
inline bool chmax(T &a, T b)
{
    if (a < b)
    {
        a = b;
        return true;
    }
    return false;
}

constexpr int inf = 1e9;
constexpr ll linf = 1e18;
constexpr ll mod = 1e9 + 7;

void solve();

int main()
{
    solve();
}

void solve()
{
    string s;
    in(s);
    int flag = 1;
    if (s.length() % 2 == 1)
    {
        flag = 0;
    }
    else
    {
        rep(i, s.length())
        {
            if (i % 2 == 0 && s[i] != 'h')
            {
                flag = 0;
                break;
            }
            else if (i % 2 == 1 && s[i] != 'i')
            {
                /* code */
                flag = 0;
            }
        }
    }
    if (flag)
    {
        out("Yes");
    }
    else
    {
        out("No");
    }
}