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.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeSet;
public class Main{
    static class Pair{
        int n;
        double res;
        public Pair(int n,double res){this.n=n;this.res=res;}
        @Override
        public String toString(){return n+" "+res;}
    }
    
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int ar[][] = new int[3][sc.nextInt()];
        for(int i =0;i<ar[0].length;i++){
            ar[0][i] = sc.nextInt();
            ar[1][i] = sc.nextInt();
        }
        int res = ar[0].length >=2 ? 2 : ar[0].length;
        ar[2][0] = -1;
        ar[2][ar[0].length-1] = 1;
        for(int i =1;i<ar[0].length-1;i++){
            if(ar[0][i] - ar[1][i] > ar[0][i-1] + ar[2][i-1]*ar[1][i-1] && ar[0][i] - ar[1][i] > ar[0][i-1]) {
                res ++;
                ar[2][i] = -1;
            }
        else if(ar[0][i] + ar[1][i] < ar[0][i+1] + ar[2][i+1]*ar[1][i+1] && ar[0][i] + ar[1][i] < ar[0][i+1]){
                res++;
                ar[2][i] = 1;
            }
        }
       
        System.out.println(res);

        
}   
}