POJ System

/*
ID: BryatnMark
LANG: JAVA
TASK: AC
 */
import java.util.*;
import java.io.*;
import java.math.*;
import java.util.*;

public class Main {
	public static void main(String args[]) throws Exception {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		Task solver = new Task();
		solver.main(in, out);
		out.close();
	}
}

class InputReader {
	BufferedReader reader;
	StringTokenizer tokenizer;

	InputReader(InputStream stream) {
		reader = new BufferedReader(new InputStreamReader(stream));
		tokenizer = null;
	}

	String next() {
		if (!hasNext())
			throw new RuntimeException();
		return tokenizer.nextToken();
	}

	boolean hasNext() {
		while (tokenizer == null || !tokenizer.hasMoreTokens())
			try {
				tokenizer = new StringTokenizer(reader.readLine());
			} catch (Exception e) {
				return false;
			}
		return true;
	}

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

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

class Task {
	BigInteger[] fact = new BigInteger[102];
	BigInteger[][] f = new BigInteger[102][102];
	BigInteger[][] c = new BigInteger[102][102];
	BigInteger one = BigInteger.ONE;
	BigInteger zero = BigInteger.ZERO, two = BigInteger.valueOf(2);

	void main(InputReader in, PrintWriter out) throws Exception {
		int i, j, k, t;
		int n = in.nextInt();
		for (i = 0; i <= n; ++i)
			c[i][0] = c[i][i] = one;
		for (i = 1; i <= n; ++i)
			for (j = 1; j < i; ++j)
				c[i][j] = c[i - 1][j - 1].add(c[i - 1][j]);
		for (i = 0; i <= n; ++i)
			for (j = 0; j * 3 <= n; ++j)
				f[i][j] = zero;
		f[3][1] = one;
		fact[0] = fact[1] = fact[2] = one;
		for (i = 3; i <= n; ++i)
			fact[i] = fact[i - 1].multiply(BigInteger.valueOf(i));
		for (i = 4; i <= n; ++i) {
			f[i][1] = fact[i - 1];
			for (j = 3; j <= i - 3; ++j) {
				t = (i - j) / 3;
				for (k = 1; k <= t; ++k) {
					f[i][k + 1] = f[i][k + 1].add(c[i][j].multiply(f[i - j][k]
							.multiply(f[j][1])));
				}
			}
			t = i / 3;
			for (k = 2; k <= t; ++k)
				f[i][k] = f[i][k].divide(BigInteger.valueOf(k));
		}

		BigInteger ans = zero;
		for (i = 1; i * 3 <= n; ++i)
			ans = ans.add(f[n][i]);
		out.println(ans);

	}
}