n=gets.to_i
mod=10**9+7

ikd=Array.new(n+1){Array.new(4){0}}
n.times do |i|
  (1..3).each do |j|
    if i==0
      if i+j<=n
        ikd[i+j][j]+=1
      end
    else
      (1..3).each do |k|
        if j!=k
          if i+j<=n
            ikd[i+j][j]+=ikd[i][k]
            ikd[i+j][j]%=mod
          end
        end
      end
    end
  end
end

puts (ikd[n][1]+ikd[n][2]+ikd[n][3])%mod