-- yukicoder My Practice
-- author: Leonardone @ NEETSDKASU

solver = function(n)
	local t, p
	
	t = {}
	p = {}
	
	for i = 1, n + 2 do
		t[i] = 0
	end
	
	t[1] = 1
	p[1] = 1
	
	repeat
		local s, c
		s = {}
		c = 0
		for i = 1, n do
			if p[i] ~= nil then
				t[i + 1] = t[i + 1] + t[i]
				t[i + 2] = t[i + 2] + t[i]
				p[i + 1] = 1
				p[i + 2] = 1
				c = c + 1
			end
		end
		p = s
	until c == 0
	
	return t[n + 1]
end

main = function()
	local n = io.read()
	local ans = solver(n)
	print(ans)
end

main()