Little Susie listens to fairy tales before bed every day. Today's fairy tale was about wood cutters and the little girl immediately started imagining the choppers cutting wood. She imagined the situation that is described below.

There are n trees located along the road at points with coordinates x1, x2, ..., xn. Each tree has its height hi. Woodcutters can cut down a tree and fell it to the left or to the right. After that it occupies one of the segments [xi - hi, xi] or [xi;xi + hi]. The tree that is not cut down occupies a single point with coordinate xi. Woodcutters can fell a tree if the segment to be occupied by the fallen tree doesn't contain any occupied point. The woodcutters want to process as many trees as possible, so Susie wonders, what is the maximum number of trees to fell. 

Input

The first line contains integer n (1 ≤ n ≤ 105) — the number of trees.

Next n lines contain pairs of integers xi, hi (1 ≤ xi, hi ≤ 109) — the coordinate and the height of the і-th tree.

The pairs are given in the order of ascending xi. No two trees are located at the point with the same coordinate.

Output

Print a single number — the maximum number of trees that you can cut down by the given rules.

Examples

Input

5
1 2
2 1
5 10
10 9
19 1


Output

3


Input

5
1 2
2 1
5 10
10 9
20 1


Output

4

Note

In the first sample you can fell the trees like that: 

  * fell the 1-st tree to the left — now it occupies segment [ - 1;1]
  * fell the 2-nd tree to the right — now it occupies segment [2;3]
  * leave the 3-rd tree — it occupies point 5
  * leave the 4-th tree — it occupies point 10
  * fell the 5-th tree to the right — now it occupies segment [19;20]



In the second sample you can also fell 4-th tree to the right, after that it will occupy segment [10;19].
import java.io.*;
import java.util.*;

public class Main implements Runnable {
    static boolean use_n_tests = false;
    static int stack_size = 1 << 27;

    void solve(FastScanner in, PrintWriter out, int testNumber) {
        int n = in.nextInt();
        int[] x = new int[n];
        int[] h = new int[n];
        for (int i = 0; i < n; i++) {
            x[i] = in.nextInt();
            h[i] = in.nextInt();
        }
        int[][] dp = new int[n + 1][3];
        dp[0][0] = 1;
        if (n == 1 || (x[0] + h[0] < x[1])) {
            dp[0][1] = 1;
        }
        dp[0][2] = 0;
        for (int i = 1; i < n; i++) {
            int leftBound = x[i] - h[i];
            if (leftBound > x[i - 1]) {
                dp[i][0] = Math.max(dp[i][0], dp[i - 1][0] + 1);
                dp[i][0] = Math.max(dp[i][0], dp[i - 1][2] + 1);
            }
            if (leftBound > x[i - 1] + h[i - 1]) {
                dp[i][0] = Math.max(dp[i][0], dp[i - 1][1] + 1);
            }
            if (i == n - 1 || (x[i] + h[i] < x[i + 1])) {
                dp[i][1] = Math.max(dp[i][1], dp[i - 1][1] + 1);
                dp[i][1] = Math.max(dp[i][1], dp[i - 1][0] + 1);
                dp[i][1] = Math.max(dp[i][1], dp[i - 1][2] + 1);
            }
            dp[i][2] = Math.max(dp[i][2], dp[i - 1][1]);
            dp[i][2] = Math.max(dp[i][2], dp[i - 1][0]);
            dp[i][2] = Math.max(dp[i][2], dp[i - 1][2]);
        }
        out.println(Math.max(dp[n - 1][0], Math.max(dp[n - 1][1], dp[n - 1][2])));
    }

    // ****************************** template code ***********

    class Pair {
        int first;
        int second;

        public int getFirst() {
            return first;
        }

        public int getSecond() {
            return second;
        }
    }

    class Multiset<T> {
        int size = 0;

        Map<T, Integer> mp = new HashMap<>();

        void add(T x) {
            mp.merge(x, 1, Integer::sum);
            size++;
        }

        void remove(T x) {
            if (mp.containsKey(x)) {
                mp.merge(x, -1, Integer::sum);
                if (mp.get(x) == 0) {
                    mp.remove(x);
                }
                size--;
            }
        }

        int size() {
            return size;
        }

        int diffSize() {
            return mp.size();
        }
    }

    static class Range {
        int l, r;
        int id;

        public int getL() {
            return l;
        }

        public int getR() {
            return r;
        }

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

    static class Array {
        static Range[] readRanges(int n, FastScanner in) {
            Range[] result = new Range[n];
            for (int i = 0; i < n; i++) {
                result[i] = new Range(in.nextInt(), in.nextInt(), i);
            }
            return result;
        }

        static public Integer[] read(int n, FastScanner in) {
            Integer[] out = new Integer[n];
            for (int i = 0; i < out.length; i++) {
                out[i] = in.nextInt();
            }
            return out;
        }

        static public int[] readint(int n, FastScanner in) {
            int[] out = new int[n];
            for (int i = 0; i < out.length; i++) {
                out[i] = in.nextInt();
            }
            return out;
        }
    }

    class Graph {
        List<List<Integer>> create(int n) {
            List<List<Integer>> graph = new ArrayList<>();
            for (int i = 0; i < n; i++) {
                graph.add(new ArrayList<>());
            }
            return graph;
        }
    }

    class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner(InputStream io) {
            br = new BufferedReader(new InputStreamReader(io));
        }

        public String line() {
            String result = "";
            try {
                result = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return result;
        }

        public String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

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

    void run_t_tests() {
        int t = in.nextInt();
        int i = 0;
        while (t-- > 0) {
            solve(in, out, i++);
        }
    }

    void run_one() {
        solve(in, out, -1);
    }

    @Override
    public void run() {
        in = new FastScanner(System.in);
        out = new PrintWriter(System.out);
        if (use_n_tests) {
            run_t_tests();
        } else {
            run_one();
        }
        out.close();
    }

    static FastScanner in;
    static PrintWriter out;

    public static void main(String[] args) throws InterruptedException {
        Thread thread = new Thread(null, new Main(), "", stack_size);
        thread.start();
        thread.join();
    }
}