#include <bits/stdc++.h>

using namespace std;

int main() {
   string S;
   while (cin >> S) {
   while (S.size() >= 2 && S.back() == 'i' && S[S.size() - 2] == 'h') {
      S.pop_back();
      S.pop_back();
   }
   cout << ((S.empty() ? "Yes\n" : "No\n"));
   }
}
