N = gets.to_i
A = 10**9 + 7

dp = Array.new(N+1){ Array.new(3){ 0 } }
dp[1][1] = 1

2.upto(N) do | i |
  dp[i][0] = (dp[i-1][1] + dp[i-1][2]) % A
  dp[i][1] = (dp[i-1][0]) % A
  dp[i][2] = (dp[i-1][1]) % A
end
p (dp[N][0] + dp[N][1] + dp[N][2]) % (10**9 + 7)