program test
implicit none
integer::a,i
integer::c=0
character*10::S
read*,S
a=len_trim(S)
if(mod(a,2)==0)then
    do i=1, a/2
    	if(S(2*i-1:2*i)=='hi')then
        	c=c+1
        end if
    end do
end if
if(c==a/2)then
	print*,'Yes'
else 
	print*,'No'
end if
end program test