import kotlin.math.*

fun int() = readLine()!!.toInt()
fun list() = readLine()!!.split(" ").map {it.toInt()}

fun main() {
	val (a,v) = list()
	val (b,w) = list()
	val t = int()
	println(if(v>w&&(abs(a-b)+v-w-1)/(v-w)<=t) "YES" else "NO")
}
