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.InputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.util.*;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class Main {

  public static void main(String[] args) {
    solve(System.in, System.out);
  }

  private static class Range {

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

    int l;
    int r;
  }

  static void solve(InputStream is, PrintStream os) {
    Scanner sc = new Scanner(is);

    /* read */
    int n = sc.nextInt();

    List<Range> ranges = new ArrayList<>(n);

    for (int i = 0; i < n; i++) {
      int x = sc.nextInt();
      int l = sc.nextInt();
      ranges.add(new Range(x - l, x + l));
    }

    ranges.sort(Comparator.comparingInt(r -> r.r));

    int reaches = Integer.MIN_VALUE;
    int removal = 0;
    for (Range range : ranges) {
      if (reaches <= range.l) {
        // its enough far.
        reaches = range.r;
      } else {
        removal++;
      }
    }


//    ranges.sort(Comparator.comparingInt(r -> r.l));
//
//    int reaches = Integer.MIN_VALUE;
//    int removal = 0;
//    for (Range range : ranges) {
//      if (reaches < range.l) {
//        // its enough far.
//        reaches = range.r;
//      } else {
//        reaches = Math.min(reaches, range.r);
//        removal++;
//      }
//    }

    os.println(n - removal);
  }

  private static class GridPointEncoder implements Encoder<GridPoint> {

    public GridPointEncoder(int h, int w) {
      this.h = h;
      this.w = w;
    }

    private final int h;
    private final int w;

    @Override
    public int num() {
      return w * h;
    }

    @Override
    public int encode(GridPoint from) {
      return w * from.r + from.c;
    }

    @Override
    public GridPoint decode(int from) {
      return new GridPoint(from / w, from % w);
    }
  }

  private static class GridPoint implements Encoded<GridPoint> {

    private final int r;
    private final int c;

    public GridPoint(int r, int c) {
      this.r = r;
      this.c = c;
    }

    @Override
    public boolean equals(Object o) {
      if (this == o) {
        return true;
      }
      if (o == null || getClass() != o.getClass()) {
        return false;
      }
      GridPoint gridPoint = (GridPoint) o;
      return r == gridPoint.r &&
          c == gridPoint.c;
    }

    @Override
    public int hashCode() {
      return Objects.hash(r, c);
    }
  }

  private static class VerticalHorizontalNeighborGridPointGraph extends GridPointGraph {

    private final boolean[][] grid;

    private final Predicate<GridPoint> predicate = this::predicate;
    private int[][] moves = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};

    public VerticalHorizontalNeighborGridPointGraph(int h, int w, boolean[][] grid) {
      super(h, w);
      this.grid = grid;
    }

    private boolean predicate(GridPoint p) {
      if (p.r < 0 || h <= p.r) {
        return false;
      }
      if (p.c < 0 || w <= p.c) {
        return false;
      }
      return grid[p.r][p.c];
    }

    private Set<Edge<GridPoint>> neighbors(GridPoint from) {

      return Arrays.stream(moves)
          .map(move -> new GridPoint(from.r + move[0], from.c + move[1]))
          .filter(predicate)
          .map(to -> new ConstantWeightEdge<>(from, to))
          .collect(Collectors.toSet());
    }

    @Override
    public Set<Edge<GridPoint>> getEdges(GridPoint from) {
      if (predicate.test(from)) {
        return neighbors(from);
      } else {
        return Collections.emptySet();
      }
    }
  }

  private static abstract class GridPointGraph extends EncodedGraph<GridPoint> {

    public GridPointGraph(int h, int w) {
      super(new GridPointEncoder(h, w));
      this.h = h;
      this.w = w;

      for (int r = 0; r < h; r++) {
        for (int c = 0; c < w; c++) {
          nodes.add(new GridPoint(r, c));
        }
      }
    }

    protected final int h;
    protected final int w;

    protected final Set<GridPoint> nodes = new HashSet<>();

    @Override
    public Set<GridPoint> getVertexes() {
      return nodes;
    }
  }

  private static interface Encoded<E extends Encoded> {

  }

  private static interface Encoder<E extends Encoded> {

    int num();

    int encode(E from);

    E decode(int from);
  }

  private static abstract class EncodedGraph<V extends Encoded<V>> implements Graph<V> {

    public EncodedGraph(Encoder<V> encoder) {
      this.encoder = encoder;
      this.delegate = new IntVertexGraph() {
        @Override
        public Set<Integer> getVertexes() {
          return EncodedGraph.this.getVertexes().stream()
              .map(encoder::encode)
              .collect(Collectors.toSet());
        }

        @Override
        public Set<Edge<Integer>> getEdges(Integer from) {
          return EncodedGraph.this.getEdges(encoder.decode(from)).stream()
              .map(e -> new Edge<>(encoder.encode(e.getFrom()), encoder.encode(e.getTo()),
                  e.getWeight()))
              .collect(Collectors.toSet());
        }
      };
    }

    private final Encoder<V> encoder;
    private final IntVertexGraph delegate;

    @Override
    public Query<V> query() {
      return new Query<V>() {

        private final Query<Integer> delegate = EncodedGraph.this.delegate.query();

        @Override
        public VertexPath<V> shortestPath(V begin, V end) {
          VertexPath<Integer> path = delegate
              .shortestPath(encoder.encode(begin), encoder.encode(end));
          if (path == null) {
            return null;
          }
          return new EfficientVertexPath<>(encoder.decode(path.getBegin()),
              encoder.decode(path.getEnd()), path.getWeight());
        }
      };
    }
  }

  private static abstract class IntVertexGraph implements Graph<Integer> {

    private static class BfsQuery implements Query<Integer> {

      final Graph<Integer> graph;

      private BfsQuery(Graph<Integer> graph) {
        this.graph = graph;
      }

      @Override
      public VertexPath<Integer> shortestPath(Integer begin, Integer end) {
        Set<Integer> visited = new HashSet<>();
        Queue<VertexPath<Integer>> queue = new ArrayDeque<>();
        queue.add(new EfficientVertexPath<>(begin));
        visited.add(begin);

        while (!queue.isEmpty()) {
          VertexPath<Integer> path = queue.remove();
          Integer head = path.getEnd();

          Set<Edge<Integer>> candidates = graph.getEdges(head);
          if (head.equals(end)) {
            return path;
          }
          for (Edge<Integer> c : candidates) {
            if (!visited.contains(c.getTo())) {
              VertexPath<Integer> p = new EfficientVertexPath<>(path, c);
              queue.add(p);
              visited.add(c.getTo());
            }
          }
        }
        return null;
      }
    }

    private static class WarshallFloydQuery implements Query<Integer> {

      private final Graph<Integer> graph;

      private VertexPath<Integer>[][] shortest;

      private WarshallFloydQuery(Graph<Integer> graph) {
        this.graph = graph;

        Set<Integer> nodes = graph.getVertexes();

        shortest = new VertexPath[nodes.size()][nodes.size()];

        for (int from : nodes) {
          Set<Edge<Integer>> edges = graph.getEdges(from);
          for (Edge<Integer> e : edges) {
            shortest[e.getFrom()][e.getTo()] = new EfficientVertexPath<>(e);
          }
          shortest[from][from] = new EfficientVertexPath<>(from);
        }

        for (int relay : nodes) {
          for (int from : nodes) {
            for (int dest : nodes) {
              VertexPath<Integer> pathA = shortest[from][relay];
              VertexPath<Integer> pathB = shortest[relay][dest];
              if (pathA != null && pathB != null) {
                VertexPath<Integer> path = pathA.append(pathB);
                if (shortest[from][dest] == null || path.getWeight() < shortest[from][dest]
                    .getWeight()) {
                  shortest[from][dest] = path;
                }
              }
            }
          }
        }
      }

      @Override
      public VertexPath<Integer> shortestPath(Integer begin, Integer end) {
        return shortest[begin][end];
      }
    }

    @Override
    public Query<Integer> query() {
      return new WarshallFloydQuery(this);
      // return new BfsQuery(this);
    }
  }

  private static interface Graph<V> {

    static class Edge<V> {

      public Edge(V from, V to, long weight) {
        this.from = from;
        this.to = to;
        this.weight = weight;
      }

      private final V from;

      private final V to;
      private final long weight;


      V getFrom() {
        return from;
      }

      V getTo() {
        return to;
      }

      long getWeight() {
        return weight;
      }
    }

    static class ConstantWeightEdge<V> extends Edge<V> {

      public ConstantWeightEdge(V from, V to) {
        super(from, to, 1);
      }
    }

    Set<V> getVertexes();

    Set<Edge<V>> getEdges(V from);

    static interface VertexPath<V> {

      V getBegin();

      V getEnd();

      long getWeight();

      VertexPath<V> append(VertexPath<V> other);
    }

    Query<V> query();

    static interface Query<V> {

      VertexPath<V> shortestPath(V begin, V end);
    }

    static class EfficientVertexPath<V> implements VertexPath<V> {

      final V begin;
      final V end;
      final long weight;

      public EfficientVertexPath(V begin) {
        this.begin = begin;
        this.end = begin;
        this.weight = 0;
      }

      public EfficientVertexPath(V begin, V end, long weight) {
        this.begin = begin;
        this.end = end;
        this.weight = weight;
      }

      public EfficientVertexPath(Edge<V> edge) {
        this.begin = edge.getFrom();
        this.end = edge.getTo();
        this.weight = edge.getWeight();
      }

      public EfficientVertexPath(VertexPath<V> path, Edge<V> append) {
        this.begin = path.getBegin();
        if (!path.getEnd().equals(append.getFrom())) {
          throw new IllegalStateException("not correct edge.");
        }
        this.end = append.getTo();
        this.weight = path.getWeight() + append.getWeight();
      }

      public EfficientVertexPath(VertexPath<V> pathA, VertexPath<V> pathB) {
        this.begin = pathA.getBegin();
        if (!pathA.getEnd().equals(pathB.getBegin())) {
          throw new IllegalStateException("not correct edge.");
        }
        this.end = pathB.getEnd();
        this.weight = pathA.getWeight() + pathB.getWeight();
      }

      @Override
      public V getBegin() {
        return begin;
      }

      @Override
      public V getEnd() {
        return end;
      }

      @Override
      public long getWeight() {
        return weight;
      }

      @Override
      public VertexPath<V> append(VertexPath<V> other) {
        return new EfficientVertexPath<>(this, other);
      }

      @Override
      public boolean equals(Object o) {
        if (this == o) {
          return true;
        }
        if (o == null || getClass() != o.getClass()) {
          return false;
        }
        EfficientVertexPath<?> that = (EfficientVertexPath<?>) o;
        return weight == that.weight &&
            Objects.equals(begin, that.begin) &&
            Objects.equals(end, that.end);
      }

      @Override
      public int hashCode() {
        return Objects.hash(begin, end, weight);
      }
    }
  }

  private static class FermatCombination {

    private long fact[];
    private long mod;

    public FermatCombination(int size, long mod) {
      this.fact = new long[size + 1];
      this.mod = mod;

      this.fact[0] = 1;

      for (int i = 1; i <= size; i++) {
        fact[i] = (fact[i - 1] * i) % mod;
      }
    }

    private long factorial(int n) {
      return fact[n];
    }

    private long inverse(long n) {
      return pow(n, mod - 2) % mod;
    }

    private long pow(long x, long n) {
      long ans = 1;
      while (n > 0) {
        if ((n & 1) == 1) {
          ans = ans * x % mod;
        }
        x = x * x % mod;
        n >>= 1;
      }
      return ans;
    }

    long combination(int n, int k) {
      long ans = 1;
      ans *= factorial(n);
      ans %= mod;
      ans *= inverse(factorial(n - k));
      ans %= mod;
      ans *= inverse(factorial(k));
      ans %= mod;
      return ans;
    }
  }

  private static class Scanner {

    private final InputStream is;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;

    Scanner(InputStream is) {
      this.is = is;
    }

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

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

    private static boolean isPrintableChar(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();
      }
      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() {
      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());
    }
  }
}
