import java.io.*;
import java.math.*;
import java.util.*;
import java.util.stream.*;

public class K {

	interface Interactor {
		int getN();

		int query(int[] p);

		int answer(int[] p);
	}

	static final int MAX_Q = 100_000;
//	static final int MAX_Q = 25_000;

	class LocalInteractor implements Interactor {
		int[] p;
		int[][] m;
		int n;

		int qryCnt = 0;

		public LocalInteractor(int n) {
			this.n = n;
			p = new int[n];
			m = new int[n][n];
			for (int i = 0; i < n; i++) {
				int j = rand(0, i);
				p[i] = p[j];
				p[j] = i;
			}
			for (int i = 0; i < n - 1; i++) {
				m[p[i]][p[i + 1]] = m[p[i + 1]][p[i]] = 1;
			}
		}

		boolean isPermutation(int[] a, int n) {
			a = a.clone();
			Arrays.sort(a);
			for (int i = 0; i < n; i++) {
				if (a[i] != i) {
					return false;
				}
			}
			return true;
		}

		@Override
		public int getN() {
			return n;
		}

		@Override
		public int query(int[] q) {
			if (!isPermutation(q, n)) {
				throw new AssertionError("Not a permutation");
			}
			if (++qryCnt > MAX_Q) {
				throw new AssertionError("Too many queries");
			}
			int ret = 0;
			for (int i = 0; i < n - 1; i++) {
				ret += m[q[i]][q[i + 1]];
			}
			return ret;
		}

		@Override
		public int answer(int[] q) {
			if (!isPermutation(q, n)) {
				throw new AssertionError("Not a permutation");
			}
			boolean eq1 = true, eq2 = true;
			for (int i = 0; i < n; i++) {
				eq1 &= p[i] == q[i];
				eq2 &= p[i] == q[n - 1 - i];
			}
			if (!eq1 && !eq2) {
				throw new AssertionError("WA");
			}
			return qryCnt;
		}
	}

	static int arrayLast(int[] arr) {
		return arr[arr.length - 1];
	}

	int solve2(Interactor it) {
		int n = it.getN();
		if (n == 2) {
			return it.answer(new int[] {0, 1});
		}
		ArrayList<int[]> pieces = new ArrayList<>();
		for (int i = 0; i < n; i++) {
			pieces.add(new int[] { i });
		}

		int[][] state = new int[n][n];

		mainCycle: while (pieces.size() > 1) {

//			int newCnt = ((LocalInteractor)it).qryCnt;
//			System.err.println((newCnt - oldCnt) + " qs used");
//			System.err.println(pieces.size() + " pieces left");
//			oldCnt = newCnt;

			Collections.shuffle(pieces, rng);
			randomFlip(pieces);

			int[] qArr = combine(pieces, 0, n);
			int base = it.query(qArr) - (n - pieces.size());
			if (base == 0) {
				markBadPairs(n, state, qArr);
				continue;
			}

			// HARD PART !!!
			// Version 1: just query all the shifts.
			int[] res = new int[pieces.size()];

			res[0] = base;

			for (int i = 1; i < pieces.size(); i++) {

				int newKek1 = arrayLast(pieces.get(Math.floorMod(i - 2, pieces.size())));
				int newKek2 = pieces.get(Math.floorMod(i - 1, pieces.size()))[0];

				int oldKek1 = arrayLast(pieces.get(Math.floorMod(i - 1, pieces.size())));
				int oldKek2 = pieces.get(i)[0];

				if (state[newKek1][newKek2] == -1 && state[oldKek1][oldKek2] == -1) {
					res[i] = res[i - 1];
					continue;
				}

				qArr = combine(pieces, i, n);
				res[i] = it.query(qArr) - (n - pieces.size());
				if (res[i] == 0 && base == 1) {
					pieces.set(i - 1, merge2(pieces.get(i - 1), pieces.get(i), state));
					pieces.remove(i);
					markBadPairs(n, state, qArr);
					continue mainCycle;
				}
			}

			int min = Integer.MAX_VALUE;
			for (int val : res) {
				min = Math.min(min, val);
			}

			int from = 0;
			// res[i] == min => i and (i - 1) are connected
			// res[i] == max => i and (i - 1) are not connected
			while (res[from] == min) {
				from++;
			}
			for (int delta = 0; delta < pieces.size();) {
				int into = (from + delta - 1) % pieces.size();
				while (delta < pieces.size() && res[(from + delta) % pieces.size()] == min) {
					int idx = (from + delta) % pieces.size();
					pieces.set(into, merge2(pieces.get(into), pieces.get(idx), state));
					pieces.set(idx, null);
					delta++;
				}
				delta++;
			}
			for (int i = pieces.size() - 1; i >= 0; i--) {
				if (pieces.get(i) == null) {
					pieces.remove(i);
				}
			}

		}
		return it.answer(pieces.get(0));
	}

	void markBadPairs(int n, int[][] state, int[] qArr) {
		for (int i = 0; i < n - 1; i++) {
			int kek1 = qArr[i];
			int kek2 = qArr[i + 1];
			if (state[kek1][kek2] == 0) {
				state[kek1][kek2] = state[kek2][kek1] = -1;
			}
		}
	}

	int[] merge2(int[] a, int[] b, int[][] state) {
		int[] ret = Arrays.copyOf(a, a.length + b.length);
		System.arraycopy(b, 0, ret, a.length, b.length);
		int kek1 = a[a.length - 1];
		int kek2 = b[0];
		state[kek1][kek2] = state[kek2][kek1] = 1;
		return ret;
	}

	int solve(Interactor it) {
//		int wasted = 0;
		int n = it.getN();
		ArrayList<int[]> pieces = new ArrayList<>();
		for (int i = 0; i < n; i++) {
			pieces.add(new int[] { i });
		}
//		int oldCnt = 0;
		mainCycle: while (pieces.size() > 1) {

//			int newCnt = ((LocalInteractor)it).qryCnt;
//			System.err.println((newCnt - oldCnt) + " qs used");
//			System.err.println(pieces.size() + " pieces left");
//			oldCnt = newCnt;

			Collections.shuffle(pieces, rng);
			randomFlip(pieces);

			int base = it.query(combine(pieces, 0, n)) - (n - pieces.size());
			if (base == 0) {
//				wasted++;
				continue;
			}

			// HARD PART !!!
			// Version 1: just query all the shifts.
			int[] res = new int[pieces.size()];

			res[0] = base;

			for (int i = 1; i < pieces.size(); i++) {
				res[i] = it.query(combine(pieces, i, n)) - (n - pieces.size());
				if (res[i] == 0 && base == 1) {
					pieces.set(i - 1, merge(pieces.get(i - 1), pieces.get(i)));
					pieces.remove(i);
					continue mainCycle;
				}
			}

			int min = Integer.MAX_VALUE;
			for (int val : res) {
				min = Math.min(min, val);
			}

			int from = 0;
			// res[i] == min => i and (i - 1) are connected
			// res[i] == max => i and (i - 1) are not connected
			while (res[from] == min) {
				from++;
			}
			for (int delta = 0; delta < pieces.size();) {
				int into = (from + delta - 1) % pieces.size();
				while (delta < pieces.size() && res[(from + delta) % pieces.size()] == min) {
					int idx = (from + delta) % pieces.size();
					pieces.set(into, merge(pieces.get(into), pieces.get(idx)));
					pieces.set(idx, null);
					delta++;
				}
				delta++;
			}
			for (int i = pieces.size() - 1; i >= 0; i--) {
				if (pieces.get(i) == null) {
					pieces.remove(i);
				}
			}

		}
//		return new int[] { it.answer(pieces.get(0)), wasted };
		return it.answer(pieces.get(0));
	}

	int[] merge(int[] a, int[] b) {
		int[] ret = Arrays.copyOf(a, a.length + b.length);
		System.arraycopy(b, 0, ret, a.length, b.length);
		return ret;
	}

	int[] combine(ArrayList<int[]> lst, int from, int tot) {
		int[] a = new int[tot];
		int ptr = 0;
		for (int i = 0; i < lst.size(); i++) {
			int j = (i + from) % lst.size();
			for (int x : lst.get(j)) {
				a[ptr++] = x;
			}
		}
		return a;
	}

	void randomFlip(ArrayList<int[]> lst) {
		for (int[] arr : lst) {
			if (rng.nextBoolean()) {
				flip(arr);
			}
		}
	}

	void flip(int[] a) {
		for (int i = 0, j = a.length - 1; i < j; i++, j--) {
			int tmp = a[i];
			a[i] = a[j];
			a[j] = tmp;
		}
	}

	void submit() {

	}

	void test() {
		int worst = 0;
		for (int tst = 0;; tst++) {
//			int[] now = solve2(new LocalInteractor(400));
//			if (now[0] > worst) {
//				System.err.println(now[0] + " after " + tst);
//				System.err.println("wasted " + now[1]);
//				worst = now[0];
//			}

			int now = solve2(new LocalInteractor(400));
			if (now > worst) {
				System.err.println(now + " after " + tst);
				worst = now;
			}
		}
//		out.println(solve2(new LocalInteractor(400)));
	}

	void stress() {
		for (int tst = 0;; tst++) {
			if (false) {
				throw new AssertionError();
			}
			System.err.println(tst);
		}
	}

	K() throws IOException {
		is = System.in;
		out = new PrintWriter(System.out);
//		submit();
		// stress();
		test();
		out.close();
	}

	static final Random rng = new Random();
	static final int C = 5;

	static int rand(int l, int r) {
		return l + rng.nextInt(r - l + 1);
	}

	public static void main(String[] args) throws IOException {
		new K();
	}

	private InputStream is;
	PrintWriter out;

	private byte[] buf = new byte[1 << 14];
	private int bufSz = 0, bufPtr = 0;

	private int readByte() {
		if (bufSz == -1)
			throw new RuntimeException("Reading past EOF");
		if (bufPtr >= bufSz) {
			bufPtr = 0;
			try {
				bufSz = is.read(buf);
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
			if (bufSz <= 0)
				return -1;
		}
		return buf[bufPtr++];
	}

	private boolean isTrash(int c) {
		return c < 33 || c > 126;
	}

	private int skip() {
		int b;
		while ((b = readByte()) != -1 && isTrash(b))
			;
		return b;
	}

	String nextToken() {
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while (!isTrash(b)) {
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}

	String nextString() {
		int b = readByte();
		StringBuilder sb = new StringBuilder();
		while (!isTrash(b) || b == ' ') {
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}

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

	char nextChar() {
		return (char) skip();
	}

	int nextInt() {
		int ret = 0;
		int b = skip();
		if (b != '-' && (b < '0' || b > '9')) {
			throw new InputMismatchException();
		}
		boolean neg = false;
		if (b == '-') {
			neg = true;
			b = readByte();
		}
		while (true) {
			if (b >= '0' && b <= '9') {
				ret = ret * 10 + (b - '0');
			} else {
				if (b != -1 && !isTrash(b)) {
					throw new InputMismatchException();
				}
				return neg ? -ret : ret;
			}
			b = readByte();
		}
	}

	long nextLong() {
		long ret = 0;
		int b = skip();
		if (b != '-' && (b < '0' || b > '9')) {
			throw new InputMismatchException();
		}
		boolean neg = false;
		if (b == '-') {
			neg = true;
			b = readByte();
		}
		while (true) {
			if (b >= '0' && b <= '9') {
				ret = ret * 10 + (b - '0');
			} else {
				if (b != -1 && !isTrash(b)) {
					throw new InputMismatchException();
				}
				return neg ? -ret : ret;
			}
			b = readByte();
		}
	}
}