import java.util.Scanner;

public class No314 {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		scanner.close();
		
		long[][] count = new long[n+1][3];
		long p = (long)Math.pow(10,9) + 7;
		
		count[1][0] = 1;
		
		for(int i = 2;i <= n;i++) {
			count[i][0] = count[i-1][2];
			count[i][1] = count[i-1][0];
			count[i][2] = (count[i-1][0] + count[i-1][1]) % p;
		}
		
		long ans = 0;
		for (long c : count[n]) {
			ans = (ans + c)% p; 
		}
		
		System.out.println(ans);

	}

}