import java.util.HashSet;
import java.util.Scanner;

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

	void run() {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] X = new int[N];
		int[] Y = new int[N];
		HashSet<Long> set = new HashSet<>();
		loop1: for (int i = 0; i < N; ++i) {
			X[i] = sc.nextInt();
			Y[i] = sc.nextInt();
			for (int x = -20 + X[i]; x <= 20 + X[i]; ++x) {
				for (int y = -20 + Y[i]; y <= 20 + Y[i]; ++y) {
					if ((x - X[i]) * (x - X[i]) + (y - Y[i]) * (y - Y[i]) >= 400)
						continue;
					if (set.contains((long) x << 32 | y)) {
						continue loop1;
					}
				}
			}
			set.add((long) X[i] << 32 | Y[i]);
		}
		System.out.println(set.size());
	}
}