#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll MOD = 1e9 + 7;

ll dp[1000010][4];

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n;
	cin >> n;
	dp[1][1] = 1;
	dp[2][2] = 1;
	dp[3][3] = 1;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= 3; j++) {
			if (i < j) break;
			for (int k = 1; k <= 3; k++) {
				if (k == j) continue;
				(dp[i][j] += dp[i - j][k]) %= MOD;
			}
		}
	}
	cout << (dp[n][1] + dp[n][2] + dp[n][3]) % MOD << endl;
	return 0;
}