import Control.Monad
import qualified Data.Text as T

solve [] = "NO"
solve (s:sl)
    | length s' > 1 = "YES"
    | otherwise     = solve sl
    where
        s' = T.splitOn (T.pack "LOVE") s

main = do
    [n, m] <- map read . words <$> getLine
    sl <- map T.pack <$> replicateM n getLine
    putStrLn $ solve sl