In a factory, there are N robots placed on a number line. Robot i is placed at coordinate X_i and can extend its arms of length L_i in both directions, positive and negative.

We want to remove zero or more robots so that the movable ranges of arms of no two remaining robots intersect. Here, for each i (1 \leq i \leq N), the movable range of arms of Robot i is the part of the number line between the coordinates X_i - L_i and X_i + L_i, excluding the endpoints.

Find the maximum number of robots that we can keep.

Constraints

* 1 \leq N \leq 100,000
* 0 \leq X_i \leq 10^9 (1 \leq i \leq N)
* 1 \leq L_i \leq 10^9 (1 \leq i \leq N)
* If i \neq j, X_i \neq X_j.
* All values in input are integers.

Input

Input is given from Standard Input in the following format:


N
X_1 L_1
X_2 L_2
\vdots
X_N L_N


Output

Print the maximum number of robots that we can keep.

Examples

Input

4
2 4
4 3
9 3
100 5


Output

3


Input

2
8 20
1 10


Output

1


Input

5
10 1
2 1
4 1
6 1
8 1


Output

5
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.function.Supplier;

public class Main {

    static void solve() {
        int n = nextInt();
        List<Point> p = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            long x = nextLong();
            long l = nextLong();
            p.add(new Point(x - l, x + l));
        }

        sort(p);

        long ans = 1;
        long right = p.get(0).right;
        for (int i = 1; i < n; i++) {
            if (right <= p.get(i).left) {
                ans++;
                right = p.get(i).right;
            }
        }

        out.println(ans);
    }

    static class Point implements Comparable<Point> {
        long left, right;

        Point(long left, long right) {
            this.left = left;
            this.right = right;
        }

        @Override
        public int compareTo(Point o) {
            return right - o.right > 0 ? 1 : -1;
        }
    }

    static final int MOD = 1_000_000_007;
    static long[] fac, finv, inv;

    // 階乗(n!)
    static long factorial(long n) {
        long ans = 1;
        for (long i = n; i > 0; i--) {
            ans = ans * i % MOD;
        }
        return ans;
    }

    // nCkの初期化
    static void comInit(int max) {
        fac = new long[max];
        finv = new long[max];
        inv = new long[max];
        fac[0] = fac[1] = 1;
        finv[0] = finv[1] = 1;
        inv[1] = 1;

        for (int i = 2; i < max; i++) {
            fac[i] = fac[i - 1] * i % MOD;
            inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
            finv[i] = finv[i - 1] * inv[i] % MOD;
        }
    }

    // nCkの計算
    static long com(int n, int k) {
        if (n < k)
            return 0;
        if (n < 0 || k < 0)
            return 0;
        return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
    }

    // 2〜nまでの数値を素因数分解したmapを返す.
    // map: 数値 -> (素因数)
    // ex)
    // 2 -> (2)
    // 4 -> (2,2)
    // 12 -> (2,2,3)
    static Map<Integer, List<Integer>> primeFactorizeTo(int n) {
        Map<Integer, List<Integer>> map = new HashMap<>();
        for (int i = 2; i <= n; i++) {
            List<Integer> list = new ArrayList<>();
            int tmp = i;
            for (int j = i - 1; j > 1; j--) {
                if (tmp % j == 0) {
                    if (map.containsKey(j)) {
                        list.addAll(map.get(j));
                    } else {
                        list.add(j);
                    }
                    tmp /= j;
                }
            }
            if (tmp != 1)
                list.add(tmp);
            map.put(i, list);
        }
        return map;
    }

    static PrintWriter out;
    static Scanner sc;
    static boolean debugEnabled;
    static long start;
    static long end;

    static int[][] newIntArray(int h, int w, int value) {
        int[][] ret = new int[h][w];
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                ret[i][j] = value;
            }
        }
        return ret;
    }

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

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

    static String nextString() {
        return sc.next();
    }

    static int[] nextIntArray(int n) {
        int[] a = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = nextInt();
        }
        return a;
    }

    static long[] nextLongArray(int n) {
        long[] a = new long[n];
        for (int i = 0; i < n; i++) {
            a[i] = nextLong();
        }
        return a;
    }

    static List<Integer> nextIntList(int n) {
        List<Integer> list = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            list.add(nextInt());
        }
        return list;
    }

    static List<Double> nextDoubleList(int n) {
        List<Double> list = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            list.add((double) nextInt());
        }
        return list;
    }

    static List<Long> nextLongList(int n) {
        List<Long> list = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            list.add(nextLong());
        }
        return list;
    }

    static char[][] nextCharArray(int h, int w) {
        char[][] c = new char[h][w];
        for (int i = 0; i < h; i++) {
            String str = nextString();
            for (int j = 0; j < w; j++) {
                c[i][j] = str.charAt(j);
            }
        }
        return c;
    }

    // 昇順
    static <T extends Comparable<? super T>> void sort(List<T> list) {
        sortAsc(list);
    }

    // 昇順
    static <T extends Comparable<? super T>> void sortAsc(List<T> list) {
        Collections.sort(list);
    }

    // 降順
    static <T extends Comparable<? super T>> void sortDesc(List<T> list) {
        Collections.sort(list, (e1, e2) -> e2.compareTo(e1));
    }

    // greatest common divisor
    // 最大公約数
    static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    // least common multiple
    // 最小公倍数
    static long lcm(long a, long b) {
        if (a > b) {
            return (a / gcd(a, b)) * b;
        } else {
            return (b / gcd(a, b)) * a;
        }
    }

    // baseのn乗を計算を返す
    static int pow(int base, int n) {
        int ret = 1;
        for (int i = 0; i < n; i++) {
            ret *= base;
        }
        return ret;
    }

    // return n^k mod m
    static long powMod(long n, long k, long m) {
        if (k == 0) {
            return 1;
        } else if (k % 2 == 1) {
            return powMod(n, k - 1, m) * n % m;
        } else {
            long tmp = powMod(n, k / 2, m);
            return tmp * tmp % m;
        }
    }

    // intをlength桁のbit文字列に変換
    static String toBitString(int length, int n) {
        StringBuilder sb = new StringBuilder();
        for (int i = length - 1; i >= 0; i--) {
            if ((n >> i) % 2 == 1) {
                sb.append("1");
            } else {
                sb.append("0");
            }
        }
        return sb.toString();
    }

    static void setDebugEnabled() {
        String className = new Object() {
        }.getClass().getEnclosingClass().getSimpleName();

        if (!className.equals("Main"))
            debugEnabled = true;
    }

    static void debug(Supplier<String> msg) {
        if (debugEnabled)
            System.err.println(msg.get());
    }

    static class UnionFind {
        int[] parent;

        UnionFind(int n) {
            parent = new int[n];
            init();
        }

        void init() {
            for (int i = 0; i < parent.length; i++) {
                parent[i] = i;
            }
        }

        int getRoot(int i) {
            if (parent[i] == i) {
                return i;
            } else {
                return parent[i] = getRoot(parent[i]);
            }
        }

        boolean isSame(int x, int y) {
            return getRoot(x) == getRoot(y);
        }

        void unit(int x, int y) {
            x = getRoot(x);
            y = getRoot(y);
            if (x != y) {
                parent[x] = y;
            }

        }
    }

    public static void main(String[] args) {
        preProcess();
        // System.exit(0)で終了した場合も、解答を出力するためにはshutdown hookの設定が必要
        // しかし、これを有効化すると100[msec]程度処理時間が長くなる
        // Runtime.getRuntime().addShutdownHook(new Thread(() -> postProcess()));
        solve();
        postProcess();
    }

    static void preProcess() {
        start = System.nanoTime();
        setDebugEnabled();
        out = new PrintWriter(System.out);
        sc = new Scanner(System.in);
    }

    static void postProcess() {
        out.flush();
        sc.close();
        end = System.nanoTime();
        debug(() -> "elapsed time: " + (end - start) / 1_000_000 + "[msec]");
    }

}
