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.Scanner;

public class Main {
	public static void main(String [] args){
		Scanner sc = new Scanner(System.in);
		TaskC a= new TaskC();
		a.solve(sc);
	}
}




class TaskC{
	
	//int [] dp = new int[10000];
	//int [] tree = new int[100005];
	
	public int solve(Scanner sc){
		int n=sc.nextInt();
		int left_index=0;
		int max_result=0;
		int x,h;
		x=sc.nextInt();
		h=sc.nextInt();
		
		left_index=x;
		//first tree always left.
		max_result++;
		if (n==1){
			System.out.println(1);
			return 0;
		}
		int i=2;
		
		int needRead=1;
		while (i<=n  || needRead == 0){
			if(needRead==1){
				x=sc.nextInt();
				h=sc.nextInt();
				i++;
			}
			//try left first;
			if (x - left_index > h){
				max_result++;
				left_index=x;
				needRead=1;
				continue;//next
			}else {
				//try right
				if( i== n+1){
					max_result++;
					i++;
					break;
				}else{
					int next_x=sc.nextInt();
					int next_h=sc.nextInt();
					i++;
					if( x+ h < next_x){
						//okay.
						left_index=x+h;
						max_result++;
					}else{
						left_index=x;
					}
					x=next_x;
					h=next_h;
					needRead=0;
				}
				
			}
		}
		
		
		System.out.println(max_result);
		return 1;


			

		
	}

}