import java.io.IOException;
import java.util.ArrayList;
import java.util.InputMismatchException;

public class Main {
	class Point implements Comparable<Point> {
		int x, y;

		Point(int x, int y) {
			this.x = x;
			this.y = y;
		}

		@Override
		public int compareTo(Point o) {
			return this.x != o.x ? this.x - o.x : this.y - o.y;
		}
	}

	boolean isIntersect(Point a, Point b) {
		return (a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y) < 400;
	}

	void run() {
		MyScanner sc = new MyScanner();

		ArrayList<Point>[] X = new ArrayList[20001];
		ArrayList<Point>[] Y = new ArrayList[20001];
		for (int i = 0; i < 20001; i++) {
			X[i] = new ArrayList<Point>();
			Y[i] = new ArrayList<Point>();
		}

		int n = sc.nextInt();
		int ans = 0;

		L: for (int i = 0; i < n; i++) {
			int x = sc.nextInt();
			int y = sc.nextInt();
			Point p = new Point(x, y);

			int maxY = Math.min(20000, y + 19);
			for (int j = Math.max(0, y - 19); j <= maxY; j++) {
				for (Point q : Y[j]) {
					if (isIntersect(p, q)) {
						continue L;
					}
//					if (p.x < q.x && !isIntersect(p, q)) {
//						break;
//					}
				}
			}
			int maxX = Math.min(20000, x + 19);
			for (int j = Math.max(0, x - 19); j <= maxX; j++) {
				for (Point q : X[j]) {
					if (isIntersect(p, q)) {
						continue L;
					}
//					if (p.y < q.y && !isIntersect(p, q)) {
//						break;
//					}
				}
			}
			X[x].add(p);
			Y[y].add(p);
			ans++;
		}
		System.out.println(ans);
	}

	public static void main(String[] args) {
		new Main().run();
	}

	public void mapDebug(int[][] a) {
		System.out.println("--------map display---------");
		for (int i = 0; i < a.length; i++) {
			for (int j = 0; j < a[i].length; j++) {
				System.out.printf("%3d ", a[i][j]);
			}
			System.out.println();
		}
		System.out.println("----------------------------" + '\n');
	}

	class MyScanner {
		int read() {
			try {
				return System.in.read();
			} catch (IOException e) {
				throw new InputMismatchException();
			}
		}

		boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		boolean isEndline(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}

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

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

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

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

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

		double[] nextDoubleArray(int n) {
			double[] array = new double[n];
			for (int i = 0; i < n; i++)
				array[i] = nextDouble();
			return array;
		}

		String next() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		String[] nextStringArray(int n) {
			String[] array = new String[n];
			for (int i = 0; i < n; i++)
				array[i] = next();

			return array;
		}

		String nextLine() {
			int c = read();
			while (isEndline(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndline(c));
			return res.toString();
		}
	}
}