#include <bits/stdc++.h>
#include <atcoder/all>
using mint = atcoder::modint1000000007;
using namespace std;

int main() {
	int n;
	cin >> n;
	vector<vector<mint>> dp(3, vector<mint> (n + 1));
	dp[0][0] = 1;
	for (int i = 1; i < n; i++){
		for (int j = 1; j < 2; j++){
			dp[j][i] += dp[j - 1][i - 1];
		}
		for (int j = 0; j < 2; j++){
			dp[2][i] += dp[j][i - 1];
		}
		dp[0][i] += dp[2][i - 1];
	}
	mint ans;
	for (int i = 0; i < 3; i++){
		ans += dp[i][n - 1];
	}
	cout << ans.val() << endl;
}