func _ (-1) _ =((1,0,0),(0,0,0))
func r 0 b=(r,b)
func (a,b,c) n _=func (c,a+c,b) (n-1) (a,b,c)
sum_ (a,b,c) =a+b+c
main = do
	n<-fmap read getLine::IO Int
	let (f,b)=func (0,1,0) (n-2) (1,0,0)
	print$(sum_ f + sum_ b) `mod` 1000000007