import java.util.Scanner;

public class Main {

	@SuppressWarnings("resource")
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		int mod=1000000007;
		long dp[]=new long[n];
		dp[0]=1;
		dp[1]=2;
		dp[2]=2;
		for(int i=3;i<n;i++){
			dp[i]=(dp[i-3]+dp[i-2])%mod;
		}
		System.out.println(dp[n-1]);
	}
}