The clique problem is one of the most well-known NP-complete problems. Under some simplification it can be formulated as follows. Consider an undirected graph G. It is required to find a subset of vertices C of the maximum size such that any two of them are connected by an edge in graph G. Sounds simple, doesn't it? Nobody yet knows an algorithm that finds a solution to this problem in polynomial time of the size of the graph. However, as with many other NP-complete problems, the clique problem is easier if you consider a specific type of a graph.

Consider n distinct points on a line. Let the i-th point have the coordinate xi and weight wi. Let's form graph G, whose vertices are these points and edges connect exactly the pairs of points (i, j), such that the distance between them is not less than the sum of their weights, or more formally: |xi - xj| ≥ wi + wj.

Find the size of the maximum clique in such graph.

Input

The first line contains the integer n (1 ≤ n ≤ 200 000) — the number of points.

Each of the next n lines contains two numbers xi, wi (0 ≤ xi ≤ 109, 1 ≤ wi ≤ 109) — the coordinate and the weight of a point. All xi are different.

Output

Print a single number — the number of vertexes in the maximum clique of the given graph.

Examples

Input

4
2 3
3 1
6 1
0 2


Output

3

Note

If you happen to know how to solve this problem without using the specific properties of the graph formulated in the problem statement, then you are able to get a prize of one million dollars!

The picture for the sample test.

<image>
/**
 * Created by Anna on 18.03.2015.
 */
/**
 * Created by Anna on 08.03.2014.
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;

public class TaskD {

    StringTokenizer st;
    BufferedReader in;
    PrintWriter out;

    public static void main(String[] args) throws NumberFormatException,
            IOException {
        TaskD solver = new TaskD();
        solver.open();
        solver.solve();
        solver.close();
    }

    public void open() throws IOException {
        in = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(System.out);
        //in = new BufferedReader(new FileReader("input.txt"));
        //out = new PrintWriter(new FileWriter("output.txt"));
    }

    public String nextToken() throws IOException {
        while (st == null || !st.hasMoreTokens()) {
            String line = in.readLine();
            if (line == null)
                return null;
            st = new StringTokenizer(line);
        }
        return st.nextToken();
    }

    public int nextInt() throws NumberFormatException, IOException {
        return Integer.parseInt(nextToken());
    }

    public long nextLong() throws NumberFormatException, IOException {
        return Long.parseLong(nextToken());
    }

    public double nextDouble() throws NumberFormatException, IOException {
        return Double.parseDouble(nextToken());
    }

    boolean hasMoreTokens() throws IOException {
        while (st == null || !st.hasMoreTokens()) {
            String line = in.readLine();
            if (line == null)
                return false;
            st = new StringTokenizer(line);
        }
        return true;
    }

    class Segment implements Comparable<Segment> {
        long start;
        long finish;

        public Segment(long x, long w) {
            this.start = x - w;
            this.finish = x + w;
        }

        @Override
        public int compareTo(Segment o) {
            return Long.compare(this.finish, o.finish);
        }

        public Long getLength() {
            return finish - start;
        }
    }


    public void solve() throws NumberFormatException, IOException {
        int n = nextInt();
        ArrayList<Segment> segments = new ArrayList<Segment>();
        for (int i = 0; i < n; i++) {
            segments.add(new Segment(nextInt(), nextInt()));
        }
        Collections.sort(segments);
        int cnt = 0;
        long lastFinish = Long.MIN_VALUE;

        for (Segment segment : segments) {
            if (segment.start >= lastFinish) {
                cnt++;
                lastFinish = segment.finish;
            }
        }

        out.println(cnt);
    }

    public void close() {
        out.flush();
        out.close();
    }
}