import java.util.*;

public class Main {
    static final int MOD = 1000000007;
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[][] dp = new int[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]) % MOD;
		    dp[i][1] = dp[i - 1][0];
		    dp[i][2] = dp[i - 1][1];
		}
		System.out.println(((dp[n][0] + dp[n][1]) % MOD + dp[n][2]) % MOD);
	}
}