import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		int d = 1000000000 + 7;
		Scanner scan = new Scanner(System.in);
		int N = scan.nextInt();
		scan.close();
		long[][] dp = new long[N + 1][3];
		dp[0][0] = 1;
		for(int i = 1; i <= N; i++) {
			dp[i][0] = (dp[i - 1][1] + dp[i - 1][2]) % d;
			dp[i][1] = dp[i - 1][0] % d;
			dp[i][2] = dp[i - 1][1] % d;
		}
		long ans = dp[N][0] + dp[N][1] + dp[N][2];
		ans = ans % d;
		System.out.println(ans);

	}
}