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.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
        int s = sc.nextInt(); long res = 0;
        initFac(s);
        for (int i = 1; i <= s; i++) {
            int rem = s - 3 * i;
            if (rem < 0) continue;
            res = (res + nck(rem + i - 1, i - 1)) % mod;
        }
        out.println(res);
        out.close();
    }

    static long[] fac;
    static long mod = (long) 1e9 + 7;

    static void initFac(long n) {
        fac = new long[(int)n + 1];
        fac[0] = 1;
        for (int i = 1; i <= n; i++) {
            fac[i] = (fac[i - 1]  * i) % mod;
        }
    }



    static long nck(int n, int k) {
        if (n < k)
            return 0;
        long den = inv((int) (fac[k] * fac[n - k] % mod));
        return fac[n] * den % mod;
    }

    static long pow(long b, long e) {
        long ans = 1;
        while (e > 0) {
            if (e % 2 == 1)
                ans = ans * b % mod;
            e >>= 1;
            b = b * b % mod;
        }
        return ans;
    }

    static long inv(long x) {
        return pow(x, mod - 2);
    }


    //-----------MyScanner class for faster input----------
    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;

        public MyScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }


    }

}