import java.util.*;

public class Exercise59{
  public static void main (String[] args){

    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();

    long m = (long)(Math.pow(10, 9) + 7);

    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 - 2] + dp[i - 3]);
    }

    System.out.println(dp[n - 1] % m);
  }
}