func main()
	var l: int :: cui@inputInt()
	var r: int :: cui@inputInt()
	var m: int :: cui@inputInt()
	var k: int :: cui@inputInt()
	
	var ans: bool :: false
	if(l * k % m = 0 | k = 0)
		do ans :: true
	elif(r * k % m = 0)
		do ans :: true
	else
		do ans :: r * k / m > l * k / m
	end if
	
	do cui@print(ans ?("Yes\n", "No\n"))
end func