import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {
	
	public static long MOD = 1000000007;
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		final int N = sc.nextInt();
		
		long[][] DP = new long[4][N + 1];
		for(int step = 1; step <= Math.min(3, N); step++){
			DP[step][step] = 1;
		}
		
		for(int pos = 1; pos < N; pos++){
			for(int prev_step = 1; prev_step <= 3; prev_step++){
				for(int step = 1; step <= 3; step++){
					if(prev_step == step){ continue; }
					
					final int next_pos = pos + step;
					if(next_pos > N){ break; }
					
					DP[step][next_pos] += DP[prev_step][pos];
					DP[step][next_pos] %= MOD;
				}
			}
		}
		
		long sum = 0;
		for(int i = 1; i <= 3; i++){
			sum += DP[i][N];
			sum %= MOD;
		}
		
		System.out.println(sum);
	}
}