package contest;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class Q476_3 {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void paint(long[] a, int inf, int sup)
	{
		if(inf>>>6 == sup>>>6){
			a[inf>>>6] |= ((sup+1&63) == 0 ? 0L : 1L<<sup+1)-(1L<<inf);
		}else{
			a[inf>>>6] |= -(1L<<inf);
			a[sup>>>6] |= ((sup+1&63) == 0 ? 0L : 1L<<sup+1)-1L;
			for(int i = (inf>>>6)+1;i < sup>>>6;i++)a[i] = -1L;
		}
	}
	
	boolean any(long[] a, int inf, int sup)
	{
		if(inf>>>6 == sup>>>6){
			return a[inf>>>6]<<~sup>>>~sup+inf != 0;
		}else{
			if(a[inf>>>6]>>>inf != 0 || a[sup>>>6]<<~sup != 0)return true;
			for(int i = (inf>>>6)+1;i < sup>>>6;i++)if(a[i] != 0)return true;
			return false;
		}
	}
	
	void solve()
	{
		int n = ni();
		long[][] map = new long[20001][22000>>>6];
		int ret = 0;
		int[] vj = new int[10];
		for(int i = 0;i < 10;i++){
			int j = (int)Math.sqrt(100-i*i);
			if(i*i+j*j == 100)j--;
			vj[i] = j;
		}
		int[] vk = new int[11];
		for(int i = 0;i < 11;i++){
			int j = (int)Math.sqrt(100-i*i);
			vk[i] = j;
		}
		outer:
		for(int z = 0;z < n;z++){
			int x = ni(), y = ni();
			// 10
			for(int i = -10;i <= 10;i++){
				if(x+i < 0 || x+i > 20000)continue;
				int inf = Math.max(0, y-vk[Math.abs(i)]);
				int sup = y+vk[Math.abs(i)];
				if(any(map[x+i], inf, sup)){
					continue outer;
				}
			}
			ret++;
			for(int i = -9;i <= 9;i++){
				if(x+i < 0 || x+i > 20000)continue;
				int inf = Math.max(0, y-vj[Math.abs(i)]);
				int sup = y+vj[Math.abs(i)];
				paint(map[x+i], inf, sup);
			}
		}
		out.println(ret);
	}
	
	void run() throws Exception
	{
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
	}
	
	public static void main(String[] args) throws Exception { new Q476_3().run(); }
	
	private byte[] inbuf = new byte[1024];
	private int lenbuf = 0, ptrbuf = 0;
	
	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }
}