n = gets.chomp.to_i
a = Array.new(2){Array.new(3,0)}
a[1][0] = 1
(n-1).times do |i|
  ni = i % 2
  pi = (i+1) % 2
  a[ni][0] = a[pi][2]
  a[ni][1] = a[pi][0]
  a[ni][2] = a[pi][0] + a[pi][1]
end
p a[(n)%2].sum%(10**9+7)