4
10 4
15 1
19 3
20 1
 2
1 999999999
1000000000 1000000000
 67
1 1
3 8
4 10
7 8
9 2
10 1
11 5
12 8
13 4
16 6
18 3
19 3
22 5
24 6
27 5
28 3
29 3
30 5
32 5
33 10
34 7
35 8
36 5
41 3
42 2
43 5
46 4
48 4
49 9
52 4
53 9
55 1
56 4
59 7
68 7
69 4
71 9
72 10
74 5
76 4
77 9
80 7
81 9
82 5
83 5
84 9
85 7
86 9
87 4
88 7
89 10
90 3
91 5
92 10
93 5
94 8
95 4
96 2
97 10
98 1
99 3
100 1
101 5
102 4
103 8
104 8
105 8
 10
999999900 1000000000
999999901 1000000000
999999902 1000000000
999999903 1000000000
999999904 1000000000
999999905 1000000000
999999906 1000000000
999999907 1000000000
999999908 1000000000
999999909 1000000000
 35
1 7
3 11
6 12
7 6
8 5
9 11
15 3
16 10
22 2
23 3
25 7
27 3
34 5
35 10
37 3
39 4
40 5
41 1
44 1
47 7
48 11
50 6
52 5
57 2
58 7
60 4
62 1
67 3
68 12
69 8
70 1
71 5
72 5
73 6
74 4
 1
1000000000 1000000000
 2
100000000 1000000000
1000000000 1000000000
 10
7 12
10 2
12 2
15 1
19 2
20 1
53 25
63 10
75 12
87 1
 3
1 1
1000 1000
1000000000 1000000000
 40
1 1
2 1
3 1
4 1
5 1
6 1
7 1
8 1
9 1
10 1
11 1
12 1
13 1
14 1
15 1
16 1
17 1
18 1
19 1
20 1
21 1
22 1
23 1
24 1
25 1
26 1
27 1
28 1
29 1
30 1
31 1
32 1
33 1
34 1
35 1
36 1
37 1
38 1
39 1
40 1

4
 2
 5
 2
 10
 1
 2
 9
 3
 2

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author Gerasimov
 */
public class Main {

    public static void main(String[] args) throws FileNotFoundException, IOException {
        PrintWriter out = new PrintWriter(System.out);
        BufferedReader inp = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(inp.readLine());
        int n = Integer.parseInt(st.nextToken());
        HashMap<Integer, Integer> mas = new HashMap<>();
        st = new StringTokenizer(inp.readLine());
        int x = Integer.parseInt(st.nextToken());
        int y = Integer.parseInt(st.nextToken());
        mas.put(1, x);

        for (int i = 0; i < n - 1; i++) {
            st = new StringTokenizer(inp.readLine());
            x = Integer.parseInt(st.nextToken());
            y = Integer.parseInt(st.nextToken());
            HashSet<Integer> hh = new HashSet<>();
            for (int j : mas.keySet()) {
                if (mas.get(j) >= x) {
                    hh.add(j);
                }
            }
            for (int j : hh) {
                mas.remove(j);
            }
            int mm = 0;
            HashMap<Integer, Integer> smas = new HashMap<>();
            for (int j : mas.keySet()) {
                int h = mas.get(j);
                if (h < x - y) {
                    if (mas.containsKey(j + 1)) {
                        if (mas.get(j + 1) > x) {
                            mas.replace(j + 1, x);
                        }
                    } else {
                        smas.put(j + 1, x);
                    }
                } else {
                    if (h < x) {
                        if (mas.containsKey(j + 1)) {
                            if (mas.get(j + 1) > x + y) {
                                mas.replace(j + 1, x + y);
                            }
                        } else {
                            smas.put(j + 1, x + y);
                        }
                    }
                }
                if (mas.get(j) < x) {
                    mas.replace(j, x);
                    if (mm < j) {
                        mm = j;
                    }
                }

            }
            
             mas.putAll(smas);
             
            hh = new HashSet<>();
            for (int j : mas.keySet()) {
                if (j < mm) {
                    hh.add(j);
                }
            }
            for (int j : hh) {
                mas.remove(j);
            }

        }
        int max = 0;
        for (int j : mas.keySet()) {
            if (max < j) {
                max = j;
            }
        }
        out.print(max);
        out.close();
    }

}