n = gets.to_i

dp = 4.times.map { Array.new(n + 1, 0) }
dp[1][1] = 1
dp[2][2] = 1
dp[3][3] = 1
dp[1][3] = 1
dp[2][3] = 1

(4 .. n).each do |j|
    dp[1][j] = dp[2][j - 1] + dp[3][j - 1] 
    dp[2][j] = dp[1][j - 2] + dp[3][j - 2] 
    dp[3][j] = dp[1][j - 3] + dp[2][j - 3] 
end
puts (dp[1][n] + dp[2][n] + dp[3][n]) % 1000_000_007