func main()
	var n: int :: cui@inputInt()
	if(n = 1)
		do cui@print("2\n")
		ret
	end if
	
	for k(2, 60)
		if(bonacci(k, n))
			do cui@print("\{k}\n")
			ret
		end if
	end for
	do cui@print("-1\n")
	
	func bonacci(k: int, n: int): bool
		var a: []int :: #[100]int
		do a[0] :: 1
		do a[1] :: 1
		var i: int :: 2
		
		while(true)
			do a[i] :: 0
			for j(1, [k, i].min())
				do a[i] :+ a[i - j]
			end for
			if(a[i] >= n)
				ret a[i] = n
			end if
			do i :+ 1
		end while
	end func
end func