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.*;

@SuppressWarnings("unused")
public class Main {

  private static void solve() {
    long s = ni();
    int mod = (int)1e9 + 7;
    int[][] fif = enumFIF(1000000, mod);
    long total = 0;
    for (int i = 1; i <= s; i ++) {
      long x = s - 3 * i;

      if (x < 0) {
        continue;
      }

      total += CX(i + x - 1, i - 1, mod, fif);
      total %= mod;
    }
    System.out.println(total);
  }

  public static long CX(long n, long r, int p, int[][] fif)
	{
		if(n < 0 || r < 0 || r > n)return 0;
		int np = (int)(n%p), rp = (int)(r%p);
		if(np < rp)return 0;
		if(n == 0 && r == 0)return 1;
		int nrp = np-rp;
		if(nrp < 0)nrp += p;
		return (long)fif[0][np]*fif[1][rp]%p*fif[1][nrp]%p*CX(n/p, r/p, p, fif)%p;
  }
  
	public static int[][] enumFIF(int n, int mod)
	{
		int[] f = new int[n+1];
		int[] invf = new int[n+1];
		f[0] = 1;
		for(int i = 1;i <= n;i++){
			f[i] = (int)((long)f[i-1] * i % mod);
		}
		long a = f[n];
		long b = mod;
		long p = 1, q = 0;
		while(b > 0){
			long c = a / b;
			long d;
			d = a; a = b; b = d % b;
			d = p; p = q; q = d - c * q;
		}
		invf[n] = (int)(p < 0 ? p + mod : p);
		for(int i = n-1;i >= 0;i--){
			invf[i] = (int)((long)invf[i+1] * (i+1) % mod);
		}
		return new int[][]{f, invf};
	}
	
  public static void main(String[] args) {
    new Thread(null, new Runnable() {
      @Override
      public void run() {
        long start = System.currentTimeMillis();
        String debug = args.length > 0 ? args[0] : null;
        if (debug != null) {
          try {
            is = java.nio.file.Files.newInputStream(java.nio.file.Paths.get(debug));
          } catch (Exception e) {
            throw new RuntimeException(e);
          }
        }
        reader = new java.io.BufferedReader(new java.io.InputStreamReader(is), 32768);
        solve();
        out.flush();
        tr((System.currentTimeMillis() - start) + "ms");
      }
    }, "", 64000000).start();
  }

  private static java.io.InputStream is = System.in;
  private static java.io.PrintWriter out = new java.io.PrintWriter(System.out);
  private static java.util.StringTokenizer tokenizer = null;
  private static java.io.BufferedReader reader;

  public static String next() {
    while (tokenizer == null || !tokenizer.hasMoreTokens()) {
      try {
        tokenizer = new java.util.StringTokenizer(reader.readLine());
      } catch (Exception e) {
        throw new RuntimeException(e);
      }
    }
    return tokenizer.nextToken();
  }

  private static double nd() {
    return Double.parseDouble(next());
  }

  private static long nl() {
    return Long.parseLong(next());
  }

  private static int[] na(int n) {
    int[] a = new int[n];
    for (int i = 0; i < n; i++)
      a[i] = ni();
    return a;
  }

  private static char[] ns() {
    return next().toCharArray();
  }

  private static long[] nal(int n) {
    long[] a = new long[n];
    for (int i = 0; i < n; i++)
      a[i] = nl();
    return a;
  }

  private static int[][] ntable(int n, int m) {
    int[][] table = new int[n][m];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[i][j] = ni();
      }
    }
    return table;
  }

  private static int[][] nlist(int n, int m) {
    int[][] table = new int[m][n];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[j][i] = ni();
      }
    }
    return table;
  }

  private static int ni() {
    return Integer.parseInt(next());
  }

  private static void tr(Object... o) {
    if (is != System.in)
      System.out.println(java.util.Arrays.deepToString(o));
  }
}
