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>
import java.io.*;
import java.util.*;

public class Solution {

    static class Point {
        final long x, y;

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

        @Override
        public String toString() {
            return "Point{" +
                    "x=" + x +
                    ", y=" + y +
                    '}';
        }
    }

    void solve() throws IOException {
        List<Point> ps = new ArrayList<>();
        int n = readInt();
        for (int i = 0; i < n; i++) {
            int x = readInt();
            int y = readInt();
            ps.add(new Point(x, y));
        }
        int r1 = tryLeftToRight(ps);
        out.println(r1);
    }

    private int tryLeftToRight(List<Point> ps) {
        ps.sort(Comparator.<Point, Long>comparing(p -> p.x + p.y));
        long maxYMinusX = Integer.MAX_VALUE;
        int r = 0;
        for (Point p : ps) {
            long curYMinusX = p.y - p.x;
            if (curYMinusX > maxYMinusX) {
                continue;
            }
            r++;
            maxYMinusX = p.y - p.x - p.y * 2;
        }
        return r;
    }

    //-------------------------------------------------

    final boolean ONLINE_JUDGE = System.getProperty("ONLINE_JUDGE") != null;

    BufferedReader in;
    PrintWriter out;
    StringTokenizer tok;

    public void run() {
        try {
            long startTime = System.currentTimeMillis();
            Locale.setDefault(Locale.US);
            if (ONLINE_JUDGE) {
                in = new BufferedReader(new InputStreamReader(System.in));
                out = new PrintWriter(System.out);
            } else {
                in = new BufferedReader(new FileReader("input.txt"));
                out = new PrintWriter("output.txt");
            }
            tok = new StringTokenizer("");
            solve();
            in.close();
            out.close();
            long endTime = System.currentTimeMillis();
            long totalMemory = Runtime.getRuntime().totalMemory();
            long freeMemory = Runtime.getRuntime().freeMemory();
            System.err.println("Time = " + (endTime - startTime) + " ms");
            System.err.println("Memory = " + ((totalMemory - freeMemory) / 1024) + " KB");
        } catch (Throwable e) {
            e.printStackTrace(System.err);
            System.exit(-1);
        }
    }

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

    int readInt() throws IOException {
        return Integer.parseInt(readString());
    }

    long readLong() throws IOException {
        return Long.parseLong(readString());
    }

    double readDouble() throws IOException {
        return Double.parseDouble(readString());
    }

    void debug(Object... o) {
        if (!ONLINE_JUDGE) {
            System.err.println(Arrays.deepToString(o));
        }
    }

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


    //------------------------------------------------------------------------------
    static class Mergesort {

        private Mergesort() {
        }

        public static void sort(int[] a) {
            mergesort(a, 0, a.length - 1);
        }

        public static void sort(long[] a) {
            mergesort(a, 0, a.length - 1);
        }

        public static void sort(double[] a) {
            mergesort(a, 0, a.length - 1);
        }

        private static final int MAGIC_VALUE = 42;

        private static void mergesort(int[] a, int leftIndex, int rightIndex) {
            if (leftIndex < rightIndex) {
                if (rightIndex - leftIndex <= MAGIC_VALUE) {
                    insertionSort(a, leftIndex, rightIndex);
                } else {
                    int middleIndex = (leftIndex + rightIndex) / 2;
                    mergesort(a, leftIndex, middleIndex);
                    mergesort(a, middleIndex + 1, rightIndex);
                    merge(a, leftIndex, middleIndex, rightIndex);
                }
            }
        }

        private static void mergesort(long[] a, int leftIndex, int rightIndex) {
            if (leftIndex < rightIndex) {
                if (rightIndex - leftIndex <= MAGIC_VALUE) {
                    insertionSort(a, leftIndex, rightIndex);
                } else {
                    int middleIndex = (leftIndex + rightIndex) / 2;
                    mergesort(a, leftIndex, middleIndex);
                    mergesort(a, middleIndex + 1, rightIndex);
                    merge(a, leftIndex, middleIndex, rightIndex);
                }
            }
        }

        private static void mergesort(double[] a, int leftIndex, int rightIndex) {
            if (leftIndex < rightIndex) {
                if (rightIndex - leftIndex <= MAGIC_VALUE) {
                    insertionSort(a, leftIndex, rightIndex);
                } else {
                    int middleIndex = (leftIndex + rightIndex) / 2;
                    mergesort(a, leftIndex, middleIndex);
                    mergesort(a, middleIndex + 1, rightIndex);
                    merge(a, leftIndex, middleIndex, rightIndex);
                }
            }
        }

        private static void merge(int[] a, int leftIndex, int middleIndex, int rightIndex) {
            int length1 = middleIndex - leftIndex + 1;
            int length2 = rightIndex - middleIndex;
            int[] leftArray = new int[length1];
            int[] rightArray = new int[length2];
            System.arraycopy(a, leftIndex, leftArray, 0, length1);
            System.arraycopy(a, middleIndex + 1, rightArray, 0, length2);
            for (int k = leftIndex, i = 0, j = 0; k <= rightIndex; k++) {
                if (i == length1) {
                    a[k] = rightArray[j++];
                } else if (j == length2) {
                    a[k] = leftArray[i++];
                } else {
                    a[k] = leftArray[i] <= rightArray[j] ? leftArray[i++] : rightArray[j++];
                }
            }
        }

        private static void merge(long[] a, int leftIndex, int middleIndex, int rightIndex) {
            int length1 = middleIndex - leftIndex + 1;
            int length2 = rightIndex - middleIndex;
            long[] leftArray = new long[length1];
            long[] rightArray = new long[length2];
            System.arraycopy(a, leftIndex, leftArray, 0, length1);
            System.arraycopy(a, middleIndex + 1, rightArray, 0, length2);
            for (int k = leftIndex, i = 0, j = 0; k <= rightIndex; k++) {
                if (i == length1) {
                    a[k] = rightArray[j++];
                } else if (j == length2) {
                    a[k] = leftArray[i++];
                } else {
                    a[k] = leftArray[i] <= rightArray[j] ? leftArray[i++] : rightArray[j++];
                }
            }
        }

        private static void merge(double[] a, int leftIndex, int middleIndex, int rightIndex) {
            int length1 = middleIndex - leftIndex + 1;
            int length2 = rightIndex - middleIndex;
            double[] leftArray = new double[length1];
            double[] rightArray = new double[length2];
            System.arraycopy(a, leftIndex, leftArray, 0, length1);
            System.arraycopy(a, middleIndex + 1, rightArray, 0, length2);
            for (int k = leftIndex, i = 0, j = 0; k <= rightIndex; k++) {
                if (i == length1) {
                    a[k] = rightArray[j++];
                } else if (j == length2) {
                    a[k] = leftArray[i++];
                } else {
                    a[k] = leftArray[i] <= rightArray[j] ? leftArray[i++] : rightArray[j++];
                }
            }
        }

        private static void insertionSort(int[] a, int leftIndex, int rightIndex) {
            for (int i = leftIndex + 1; i <= rightIndex; i++) {
                int current = a[i];
                int j = i - 1;
                while (j >= leftIndex && a[j] > current) {
                    a[j + 1] = a[j];
                    j--;
                }
                a[j + 1] = current;
            }
        }

        private static void insertionSort(long[] a, int leftIndex, int rightIndex) {
            for (int i = leftIndex + 1; i <= rightIndex; i++) {
                long current = a[i];
                int j = i - 1;
                while (j >= leftIndex && a[j] > current) {
                    a[j + 1] = a[j];
                    j--;
                }
                a[j + 1] = current;
            }
        }

        private static void insertionSort(double[] a, int leftIndex, int rightIndex) {
            for (int i = leftIndex + 1; i <= rightIndex; i++) {
                double current = a[i];
                int j = i - 1;
                while (j >= leftIndex && a[j] > current) {
                    a[j + 1] = a[j];
                    j--;
                }
                a[j + 1] = current;
            }
        }

    }

}