import Control.Applicative
import Data.Bool (bool)

main :: IO ()
main = solve <$> f <*> f <*> readLn >>= putStrLn
  where
    f = map read <$> words <$> getLine

solve :: [Int] -> [Int] -> Int -> String
solve [a, v] [b, w] t = bool "NO" "YES" $ v > w && abs (a - b) <= (v - w) * t
