func main()
	var s: []char :: cui@input()
	var n: int :: 0
	if(^s > 2)
		do n :: [s[^s - 2], s[^s - 1]].toInt(&)
	else
		do n :: s.toInt(&)
	end if
	var ans: int :: 1
	if(n % 2 = 0)
		if(n = 4)
			do ans :: -1
		else
			if(n % 4 <> 0)
				do ans :: -1
			end if
		end if
	end if
	do cui@print("\{ans}\n")
end func