N = gets.to_i
dp = Array.new(N + 1, 0)
dp[0] = 1
dp[1] = 1
dp[2] = 2
3.upto(N) do |i|
  dp[i] = (dp[i - 2] + dp[i - 3]) % (10**9 + 7)
end
ans = dp[N]
puts ans