import Data.Maybe
import Control.Monad
import qualified Data.ByteString.Char8 as C

x ? (a,b) = if x then a else b

main = do
 n <- getLine
 putStr $ (solve n)?("Yes","No")

solve :: String -> Bool
solve [] = True
solve [a] = False
solve s@(a:b:x)
 | take 2 s == "hi" = solve x
 | otherwise = False
