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.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.NoSuchElementException;

class Main {

  static class Solver {
    final FastScanner sc;
    final PrintWriter writer;

    Solver(final FastScanner sc, final PrintWriter writer) {
      this.sc = sc;
      this.writer = writer;
    }

    void run() {
      int n = sc.nextInt();
      Robot[] robots = new Robot[n];
      for (int i = 0; i < n; i++) {
        int[] val = sc.nextIntArray(2);
        robots[i] = new Robot(val[0] - val[1], val[0] + val[1]);
      }
      Arrays.sort(robots);
      int result = 0;
      int cursor = Integer.MIN_VALUE;
      for (int i = 0; i < n; i++) {
        if (cursor <= robots[i].left) {
          result++;
          cursor = robots[i].right;
        }
      }
      writer.println(result);
    }
  }

  static class Robot implements Comparable<Robot> {
    int left, right;

    public Robot(int left, int right) {
      this.left = left;
      this.right = right;
    }

    @Override
    public int compareTo(Robot r) {
      if (this.right != r.right) {
        return this.right - r.right;
      }
      return this.left - r.left;
    }
  }

  public static void main(final String[] args) {
    final FastScanner sc = new FastScanner();
    final PrintWriter w = new PrintWriter(System.out);
    new Solver(sc, w).run();
    w.flush();
    w.close();
  }

  // CRT stuff
  static class MOD {
    private static final int MOD = (int) 1e9 + 7;

    static long plus(long x, long y) {
      x %= MOD;
      y %= MOD;
      return (x + y) % MOD;
    }

    static long sub(long x, long y) {
      x %= MOD;
      y %= MOD;
      return (x - y + MOD) % MOD;
    }

    static long multi(long x, long y) {
      x %= MOD;
      y %= MOD;
      return x * y % MOD;
    }

    static long div(long x, long y) {
      x %= MOD;
      y %= MOD;
      return x * pow(y, MOD - 2) % MOD;
    }

    static long pow(final long a, final long p) {
      if (p == 0)
        return 1;
      if (p % 2 == 0) {
        final long halfP = p / 2;
        final long root = pow(a, halfP);
        return root * root % MOD;
      } else
        return a * pow(a, p - 1) % MOD;
    }
  }

  // FastScanner
  static class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;

    public FastScanner() {
    }

    private boolean hasNextByte() {
      if (ptr < buflen) {
        return true;
      } else {
        ptr = 0;
        try {
          buflen = in.read(buffer);
        } catch (final IOException e) {
          e.printStackTrace();
        }
        if (buflen <= 0) {
          return false;
        }
      }
      return true;
    }

    private int readByte() {
      if (hasNextByte())
        return buffer[ptr++];
      else
        return -1;
    }

    private boolean isPrintableChar(final int c) {
      return 33 <= c && c <= 126;
    }

    public boolean hasNext() {
      while (hasNextByte() && !isPrintableChar(buffer[ptr]))
        ptr++;
      return hasNextByte();
    }

    public String next() {
      if (!hasNext())
        throw new NoSuchElementException();
      final StringBuilder sb = new StringBuilder();
      int b = readByte();
      while (isPrintableChar(b)) {
        sb.appendCodePoint(b);
        b = readByte();
      }
      return sb.toString();
    }

    public long nextLong() {
      if (!hasNext())
        throw new NoSuchElementException();
      long n = 0;
      boolean minus = false;
      int b = readByte();
      if (b == '-') {
        minus = true;
        b = readByte();
      }
      if (b < '0' || '9' < b) {
        throw new NumberFormatException();
      }
      while (true) {
        if ('0' <= b && b <= '9') {
          n *= 10;
          n += b - '0';
        } else if (b == -1 || !isPrintableChar(b)) {
          return minus ? -n : n;
        } else {
          throw new NumberFormatException();
        }
        b = readByte();
      }
    }

    public int nextInt() {
      final long nl = nextLong();
      if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE)
        throw new NumberFormatException();
      return (int) nl;
    }

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

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

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