func main()
	var _: [][]char :: cui@input().split(" ")
	var H: int :: _[0].toInt(&)
	var W: int :: _[1].toInt(&)
	var N: int :: _[2].toInt(&)
	var K: int :: _[3].toInt(&)
	var ans: bool :: H * W % N = K % N
	do cui@print(ans ?("YES\n", "NO\n"))
end func