import java.util.Scanner;

public class Main{
	
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		
		// input
		final int NUM = scan.nextInt();
		long[] kenpa = new long[NUM+1];
		
		// search
		for(int i = 1; i <= NUM; i++){
			if(i == 1){
				kenpa[1] = 1;
			} else if(i == 2){
				kenpa[2] = 2;
			} else if(i == 3){
				kenpa[3] = 2;
			} else {
				kenpa[i] = kenpa[i-2] % 1000000007 + kenpa[i-3] % 1000000007;
			}
		}
		
		// answer
		System.out.println(kenpa[NUM] % 1000000007);
		
		
	}
}