import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		long[] x = new long[n];
		long[] y = new long[n];
		for (int i = 0; i < n; i++) {
			x[i] = sc.nextLong();
			y[i] = sc.nextLong();
		}
		sc.close();

		int ans = 0;
		for (int i = 0; i < n; i++) {
			Map<String, List<Integer>> map = new HashMap<>();
			for (int j = 0; j < n; j++) {
				if (j != i) {
					long dx = x[j] - x[i];
					long dy = y[j] - y[i];
					String s = "inf";
					if (dx != 0) {
						if (dx < 0) {
							dx = -dx;
							dy = -dy;
						}
						long g = gcd(dx, Math.abs(dy));
						dx /= g;
						dy /= g;
						s = dy + "/" + dx;
					}
					List<Integer> list = map.get(s);
					if (list == null) {
						list = new ArrayList<>();
						map.put(s, list);
					}
					list.add(j);
				}
			}
			label:
			for (String s : map.keySet()) {
				List<Integer> list = map.get(s);
				if (list.size() < 2) {
					continue;
				}
				list.add(i);
				long[] z = s.equals("inf") ? y : x;
				int size = list.size();
				Obj[] arr = new Obj[size];
				for (int j = 0; j < size; j++) {
					Obj o = new Obj();
					o.i = list.get(j);
					o.x = z[o.i];
					arr[j] = o;
				}
				Arrays.sort(arr, (o1, o2) -> Long.compare(o1.x, o2.x));
				for (int j = 0; j < size; j++) {
					Obj o = arr[j];
					if (o.i == i && (j >= 2 || j < size - 2)) {
						ans++;
						break label;
					}
				}
			}
		}
		System.out.println(ans);
	}

	static class Obj {
		int i;
		long x;
	}

	static long gcd(long a, long b) {
		return b == 0 ? a : gcd(b, a % b);
	}
}