#include<bits/stdc++.h>
using namespace std;
const int M=1000000007;
const int N=1000005;
int i,n;
char c[15];
int main()
{
	scanf("%s",c);
	for(i=0;c[i];i+=2)
		if(!(c[i]=='h'&&c[i+1]=='i'))
		{
			puts("No");
			return 0;
		}
	puts("Yes");
}