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.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.math.BigInteger;

public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		FastInput in = new FastInput(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		ABC178D solver = new ABC178D();
		solver.solve(1, in, out);
		out.close();
	}
	
	static class ABC178D {
	
		static int mod = 1000000007;
		static int n;
		static long[] fac;
		static long[] finv;
		
		public void solve(int testNum, FastInput in, PrintWriter out) {
			
			n = in.nextInt();
			
			if(n < 3) {
				out.println(0);
				return;
			}
			int []dp = new int [n+1];
			dp[0] = 1;
			dp[1] = dp[2] = 0;
			
			for(int i = 3; i <= n ; i++) {
				for(int j = 0 ; j <= i-3 ; j++) {
					dp[i] = (dp[i] + dp[j])%mod;
				}
			}
			
			out.println(dp[n]);
		}
}
static class FastInput{
	private final BufferedReader in;
	private String[] buff;
	private int index = 0;
	
	public FastInput(InputStream is) {
		in = new BufferedReader(new InputStreamReader(is));
	}
	String nextLine() {
		try {
			return in.readLine();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}
	String next() {
		while (buff == null || index >= buff.length) {
			buff = nextLine().split(" ");
			index = 0;
		}
		return buff[index++];
	}
	int nextInt() {
		return Integer.parseInt(next());
	}
	
	long nextLong() {
		return Long.parseLong(next());
	}
	
	Double nextDouble() {
		return Double.parseDouble(next());
	}
	
	BigInteger nextBigInteger() {
		return new BigInteger(next());
	}
	
	BigDecimal nextBigDecimal() {
		return new BigDecimal(next());
	}
	
	public int[] nextIntArray(final int n) {
		final int[] res = new int [n];
		
		for(int i = 0 ; i < n ;i++) {
			res[i] = nextInt();
		}
		return res;
	}
	
	public long[] nextLongArray(final int n) {
		final long[] res= new long [n];
		
		for(int i = 0 ; i < n ;i++) {
			res[i] = nextLong();
		}
		return res;
	}
	
	public double[] nextDoubleArray(final int n ) {
		final double[] res = new double [n];
		
		for(int i = 0 ; i < n ;i++) {
			res[i] = nextDouble();
		}
		return res;
	}
	
	
	public int[][] nextInt2DArray(final int n , final int m){
		int [][]res = new int [n][m];
		
		for(int i = 0 ; i < n ;i++) {
			for(int j = 0 ; j < m ;j++) {
				res[i][j] = nextInt();
			}
		}
		return res;
	}
	public long[][] nextLong2DArray(final int n , final int m){
		long [][]res = new long [n][m];
		
		for(int i = 0 ; i < n ;i++) {
			for(int j = 0 ; j < m ;j++) {
				res[i][j] = nextLong();
			}
		}
		return res;
	}
	
	public char[][] nextChar2DArray(final int n){
		char [][]res = new char [n][];
		
		for(int i = 0 ; i < n ;i++) {
			String s = next();
			res[i] = s.toCharArray();
		}
		
		return res;
	}
}

}
