#include <iostream>
using namespace std;

long long DP[1000001];

int main()
{
	int N;
	cin >> N;
	DP[0] = 1;
	DP[2] = 1;
	for (int i = 3; i <= N; i++) {
		DP[i] = (DP[i - 3] + DP[i - 2]) % (int)(1e9 + 7);
	}

	if (N == 1)cout << 1 << endl;
	else cout << (DP[N] + DP[N - 1] + DP[N - 2])%(int)(1e9+7) << endl;

    return 0;
}