import java.io.*;
import java.util.*;

class Main314 {
	
	public static long solve (int n) {
		if (n == 1) return 1;
		if (n <= 3) return 2;
		
		long[] p = new long[n];
		int m = 1000000007;
		
		p[1] = 0;
		if (n > 2) p[2] = 1;
		if (n > 3) p[3] = 1;
		for (int i = 4; i < n; i++)
			p[i] = (p[i - 2] + p[i - 3]) % m;
		
		return (p[n - 1] + 2 * p[n - 2] + p[n - 3]) % m;
	}
	
	public static void out (Object o) {
		System.out.println(o);
	}
	
	public static void main (String[] args) throws IOException {
		BufferedReader br = 
			new BufferedReader(new InputStreamReader(System.in));
		
		int n = Integer.parseInt(br.readLine());
		
		out(solve(n));
		
	}
}