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.*;
import java.util.*;

public class No545C {
  public static void main (String [] args) throws IOException {
    No545C program = new No545C();
    program.solve();
    
  }
  int n;
  Tree[] trees;
  
  public void solve() throws IOException {
    /*Scanner sc = null;
    try {
      sc = new Scanner(new File("C:/Users/John/workspace/CodeForces/src/input.txt"));
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    }*/
    Scanner sc = new Scanner(System.in);
    n = sc.nextInt();
    
    if (n <= 2) {
      System.out.println(n);
      return;
    }
    trees = new Tree[n];

    int numCuts = 0;
    
    int coordinate = sc.nextInt();
    int height = sc.nextInt();
    trees[0] = new Tree(0, coordinate, height, Status.LEFT);
    numCuts++;
    
    for (int i = 1; i < n - 1; i++) {
      coordinate = sc.nextInt();
      height = sc.nextInt();
      trees[i] = new Tree(i, coordinate, height, Status.UNCUT);

      Tree prev = trees[i - 1];
      
      switch(prev.status) {
        case UNCUT: {
          // cut prev right and cur left for free
          if (prev.coordinate + prev.height < coordinate - height) {
            trees[i - 1].status = Status.RIGHT;
            trees[i].status = Status.LEFT;
            numCuts += 2;
          } 
          // cut prev right. cur can't cut left
          else if (prev.coordinate + prev.height < coordinate) {
            trees[i - 1].status = Status.RIGHT;
            numCuts++;
          }
          // if prev can't be cut, cut cur left
          else if (prev.coordinate < coordinate - height) {
            trees[i].status = Status.LEFT;
            numCuts++;
          }
          break;
        }
        case LEFT: {
          // cut current left for free
          if (prev.coordinate < coordinate - height) {
            trees[i].status = Status.LEFT;
            numCuts++;
          }
          break;
        }
        default:
      }
    }
    coordinate = sc.nextInt();
    height = sc.nextInt();
    trees[n - 1] = new Tree(n - 1, coordinate, height, Status.RIGHT);
    numCuts++;

    if (trees[n - 2].status == Status.UNCUT && trees[n - 2].coordinate + trees[n - 2].height < trees[n - 1].coordinate) {
      trees[n - 2].status = Status.RIGHT;
      numCuts++;
    }

    System.out.println(numCuts);
  }
  
  
  class Tree {
    int i;
    int coordinate;
    int height;
    Status status;
    
    public Tree (int i, int coordinate, int height, Status s) {
      this.i = i;
      this.coordinate = coordinate;
      this.height = height;
      this.status = s;
    }
  }
  
  enum Status {
    LEFT, RIGHT, UNCUT
  }
}