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.

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// package cf.cf527;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;
import java.util.function.IntConsumer;

public class CFD {
    private static final String INPUT = "4\n" +
            "2 3\n" +
            "3 1\n" +
            "6 1\n" +
            "0 2\n";
    private static final int MOD = 1_000_000_007;

    FastScanner sc;
    PrintWriter out;

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

    public CFD() {
        sc = new FastScanner(oj ? System.in : new ByteArrayInputStream(INPUT.getBytes()));
        out = new PrintWriter(System.out);
    }

    public void run() {
        long start = System.currentTimeMillis();
        times(1, this::solve);
        out.flush();
        tr(System.currentTimeMillis() - start + "ms");
    }

    static class Range {
        int l, r;

        public Range(int l, int r) {
            this.l = l;
            this.r = r;
        }
    }

    public void solve(int time) {
        int n = sc.nextInt();
        Range[] ranges = new Range[n];
        for (int i = 0; i < n; i++) {
            int c = sc.nextInt();
            int r = sc.nextInt();
            ranges[i] = new Range(c - r, c + r);
        }
        Arrays.sort(ranges, Comparator.comparingInt((Range r) -> r.l).thenComparingInt(r -> r.r));

        int ans = 1;
        Range prevRange = ranges[0];
        for (int i = 1; i < ranges.length; i++) {
            Range range = ranges[i];
            if (range.r < prevRange.r) {
                prevRange = range;
            } else if (range.l >= prevRange.r) {
                ans++;
                prevRange = range;
            }
        }
        answer(ans);
    }

    int binSearch(int m, int c, int step, int goal, int l, int r) { // l inclusive, r exclusive
        while (l < r - 1) {
            int med = (l + r) / 2;
            if (m + med * step > goal) {
                r = med;
            } else {
                l = med;
            }
        }
        return l;
    }

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

    /**
     * If searched element doesn't exist, returns index of first element which is bigger than searched value.<br>
     * If searched element is bigger than any array element function returns first index after last element.<br>
     * If searched element is lower than any array element function returns index of first element.<br>
     * If there are many values equals searched value function returns first occurrence.<br>
     */
    private static int lowerBound(long[] arr, long key) {
        int lo = 0;
        int hi = arr.length - 1;
        while (lo < hi) {
            int mid = (lo + hi) / 2;
            if (key <= arr[mid]) {
                hi = mid - 1;
            } else {
                lo = mid + 1;
            }
        }
        return arr[lo] < key ? lo + 1 : lo;
    }

    /**
     * Returns index of first element which is grater than searched value.
     * If searched element is bigger than any array element, returns first index after last element.
     */
    private static int upperBound(long[] arr, long key) {
        int lo = 0;
        int hi = arr.length - 1;
        while (lo < hi) {
            int mid = (lo + hi) / 2;
            if (key >= arr[mid]) {
                lo = mid + 1;
            } else {
                hi = mid;
            }
        }
        return arr[lo] <= key ? lo + 1 : lo;
    }

    private long[] prefixSum(long[] array) {
        long[] result = new long[array.length];
        result[0] = array[0];
        for (int i = 1; i < array.length; i++) result[i] = result[i - 1] + array[i];
        return result;
    }

    private int[] sort(int[] array) {
        shuffle(array);
        Arrays.sort(array);
        return array;
    }

    private static void shuffle(int[] array) {
        Random random = new Random();
        for (int i = array.length - 1; i > 0; i--) {
            int index = random.nextInt(i + 1);
            {
                int tmp = array[index];
                array[index] = array[i];
                array[i] = tmp;
            }
        }
    }

    private long[] sort(long[] array) {
        shuffle(array);
        Arrays.sort(array);
        return array;
    }

    private static void shuffle(long[] array) {
        Random random = new Random();
        for (int i = array.length - 1; i > 0; i--) {
            int index = random.nextInt(i + 1);
            {
                long tmp = array[index];
                array[index] = array[i];
                array[i] = tmp;
            }
        }
    }

    static class ExitException extends RuntimeException {
    }

    private int iread() {
        int res = sc.nextInt();
        if (res <= 0) {
            throw new ExitException();
        }
        return res;
    }

    private void iwrite(char[] chars) {
        for (char chr : chars) {
            out.print(chr);
        }
        out.println();
        out.flush();
    }

    private void write(Object obj) {
        out.print(obj);
    }

    private void writeln(Object obj) {
        out.println(obj);
    }

    private void writeln() {
        out.println();
    }

    private void answer(Object ans) {
        out.println(ans);
        throw new ExitException();
    }

    private void times(int n, IntConsumer consumer) {
        for (int i = 0; i < n; i++) {
            try {
                consumer.accept(i);
            } catch (ExitException ignored) {
            }
        }
    }

    private int[] readIntArray(int n) {
        int[] res = new int[n];
        for (int i = 0; i < n; i++) {
            res[i] = sc.nextInt();
        }
        return res;
    }

    private long[] readLongArray(int n) {
        long[] res = new long[n];
        for (int i = 0; i < n; i++) {
            res[i] = sc.nextLong();
        }
        return res;
    }

    static class FastScanner {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;

        FastScanner(InputStream stream) {
            this.stream = stream;
        }

        int read() {
            if (numChars == -1)
                throw new InputMismatchException();
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) return -1;
            }
            return buf[curChar++];
        }

        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;
        }

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

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

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

        public 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();
        }

        public 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();
        }

    }

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

    private void tr(Object... o) {
        if (!oj) System.out.println(Arrays.deepToString(o));
    }
}
