Given is an integer S. Find how many sequences there are whose terms are all integers greater than or equal to 3, and whose sum is equal to S. The answer can be very large, so output it modulo 10^9 + 7.

Constraints

* 1 \leq S \leq 2000
* All values in input are integers.

Input

Input is given from Standard Input in the following format:


S


Output

Print the answer.

Examples

Input

7


Output

3


Input

2


Output

0


Input

1729


Output

294867501

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Main {

   private static final String INPUT_FILE_PATH = "";
   
   static final int MOD = (int) (1e9 + 7);

   static void solve(InputReader in, PrintWriter out) {
      int s = in.nextInt();

      if (s < 3) {
         out.println(0);
         return;
      }

      long[] dp = new long[s + 1];
      dp[0] = 1;
      dp[3] = 1;
      for (int i = 4; i <= s; i++) {
         for (int j = 3; j <= i; j++) {
            dp[i] += dp[i - j];
            dp[i] %= MOD;
         }
      }
      out.println(dp[s]);
   }

   private static class InputReader {
      private BufferedReader br;
      private StringTokenizer st;

      public InputReader(InputStream inputStream) {
         this.br = new BufferedReader(new InputStreamReader(inputStream), 32768);
         this.st = null;
      }

      public String nextToken() {
         while (st == null || !st.hasMoreTokens()) {
            try {
               st = new StringTokenizer(br.readLine());
            } catch (IOException e) {
               throw new RuntimeException(e);
            }
         }
         return st.nextToken();
      }

      public int nextInt() {
         return Integer.parseInt(nextToken());
      }

      public long nextLong() {
         return Long.parseLong(nextToken());
      }

      public double nextDouble() {
         return Double.parseDouble(nextToken());
      }
   }

   public static void main(String[] args) throws Exception {
      InputStream inputStream = INPUT_FILE_PATH.isEmpty()
         ? System.in
         : new FileInputStream(new File(INPUT_FILE_PATH));
      OutputStream outputStream = System.out;

      InputReader inputReader = new InputReader(inputStream);
      PrintWriter printWriter = new PrintWriter(outputStream);

      solve(inputReader, printWriter);

      printWriter.close();
   }

}
