object Main extends App{
  val sc = new java.util.Scanner(System.in)
  var a,v= sc.nextLong()
  var b,w= sc.nextLong()
  var t= sc.nextLong()
  var av = BigInt(a+(v*t))
  var bw = BigInt(b+(w*t))
  print(if (av >= bw) "YES" else "NO")
}
