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) throws Exception {
        FastScanner sc = new FastScanner(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        long mod = (long)1e9+7;
        Combination comb = new Combination(10000);
        int s = sc.nextInt();
        long ans = 0;
        int max = s/3;
        for(int i = 1; i <= max; i++){
            int rem = s-3*i;
            long tmp = Combination.comb(rem+i-1,rem);
            ans += tmp;
            ans %= mod;
        }
        pw.println(ans);
        pw.flush();
    }
    
    static class GeekInteger {
        public static void save_sort(int[] array) {
            shuffle(array);
            Arrays.sort(array);
        }
 
        public static int[] shuffle(int[] array) {
            int n = array.length;
            Random random = new Random();
            for (int i = 0, j; i < n; i++) {
                j = i + random.nextInt(n - i);
                int randomElement = array[j];
                array[j] = array[i];
                array[i] = randomElement;
            }
            return array;
        }
    }
    
}

class Combination {
    final static long mod = (long)Math.pow(10,9)+ 7;
    private static long[] fact, ifact;
    public Combination(int n){
        fact = new long[n+1];
        ifact = new long[n+1];
        fact[0] = 1;
        long ln = n;
        for (long i = 1; i <= ln; ++i){
            int ii = (int)i;
            fact[ii] = fact[ii-1]%mod * i % mod;
        }
        ifact[n] = pow(fact[n],this.mod-2);
        for (int i = n; i >= 1; --i){
            int ii = (int)i;
            ifact[ii-1] = ifact[ii]%mod*i%mod;
        }
    }
    
    public static long comb(int n, int k){
        if (k < 0 || k > n) return 0;
        return fact[n] % mod * ifact[k] % mod * ifact[n-k] % mod;
    }
    
    public static long perm(int n, int k){
        return comb(n,k) * fact[k] % mod;
    }
    
    public static long pow(long a,long b) {
        long ret = 1;
        long tmp = a;
        while(b>0) {
            if((b&1)==1){
                ret = (ret * tmp) % mod;
            }
            tmp = (tmp * tmp) % mod;
            b = b>>1;
        }
        return ret;
    }
}

class FastScanner {
    private BufferedReader reader = null;
    private StringTokenizer tokenizer = null;
    public FastScanner(InputStream in) {
        reader = new BufferedReader(new InputStreamReader(in));
        tokenizer = null;
    }

    public String next() {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken();
    }

    public String nextLine() {
        if (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                return reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken("\n");
    }

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

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

    public double nextDouble() {
         return Double.parseDouble(next());
    }
    
    public String[] nextArray(int n) {
        String[] a = new String[n];
        for (int i = 0; i < n; i++)
            a[i] = next();
        return a;
    }

    public int[] nextIntArray(int n) {
        int[] a = new int[n];
        for (int i = 0; i < n; i++)
            a[i] = nextInt();
        return a;
    }

    public long[] nextLongArray(int n) {
        long[] a = new long[n];
        for (int i = 0; i < n; i++)
            a[i] = nextLong();
        return a;
    } 
}
