M = 10**9+7

$dp = {}
def f(n, i, level=0)
  $dp[[n,i]] ||= if n == 0
    1
  elsif n < 0
    0
  else
    [1,2,3].map{|j|
      if j == i
       0
      elsif level > 200
        Fiber.new { f(n - j, j, 0) }.resume
      else
        f(n - j, j, level+1)
      end
    }.sum % M
  end
end

N = gets.to_i
p f(N, 0)