MOD = 1000000007
n = gets.to_i
if n == 1
    p 1
elsif n < 4
    p 2
else
    a = Array.new(n)
    a[0..2] = [1,2,2]
    3.upto(n - 1){|i|
        a[i] = (a[i - 3] + a[i - 2]) % MOD
        }
    p a[n - 1]
end