import java.util.Scanner;

public class N314
{
	static int cnt=0;
	static int n;
	public static void main(String[] args)
	{
		Scanner sc=new Scanner(System.in);
		n=sc.nextInt();
		int length=2;
		int[] state=new int[3];
		int[] buf=new int[3];
		int beki=(int)Math.pow(10, 9)+7;
		state[0]=1;state[1]=1;state[2]=0;
		if(n>2)
		{
			while(length!=n)
			{
				for(int i=0;i<3;i++)
				{
					buf[i]=state[i];
				}
				state[0]=buf[2]%beki;
				state[1]=(buf[0]+buf[2])%beki;
				state[2]=buf[1]%beki;
				length++;
			}
			for(int i=0;i<3;i++)
			{
				cnt+=state[i];
			}
		}
		else
		{cnt=n;}
		System.out.println(cnt%beki);
	}
}