#include <iostream>
#include <cstdio>
#include <vector>

using namespace std;

int mod = 1e9 + 7;

int main() {
	int n;

	cin >> n;

	vector< vector<long long> >  dp(n + 1, vector<long long>(3, 0));
	dp[0][0] = 1;


	for (int i = 1; i <= n; i++) {
		dp[i][0] += dp[i-1][1] + dp[i-1][2];
		dp[i][1] += dp[i-1][0];
		dp[i][2] += dp[i-1][1];

		dp[i][0] %= mod;
		dp[i][1] %= mod;
		dp[i][2] %= mod;
	}

	long long ans = (dp[n][0] + dp[n][1] + dp[n][2]) % mod;
	cout << ans << endl;
	return 0;
}