class Yukicoder
  KEN = 0
  PAR = 1
  KENKEN = 2
  MOD = 10 ** 9 + 7

  def initialize
    n = gets.chomp.to_i

    dp = Array.new(n+1){ Array.new(3, 0)}
    dp[1][KEN] = 1

    2.upto(n) do |i|
      dp[i][KEN] = dp[i-1][PAR]
      dp[i][PAR] = dp[i-1][KEN] + dp[i-1][KENKEN]
      dp[i][KENKEN] = dp[i-1][KEN]
    end

    puts dp[n].inject(:+) % MOD
  end
end

Yukicoder.new