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 static java.lang.System.*;
import java.util.*;
import java.io.*;
public class Woodcutters 
{
	public static void main(String[] args)
	{
		Scanner in = new Scanner(System.in);
		int trees = in.nextInt();
		Tree previous = null;
		int tot = 0;
		int lBound = 0;
		for(int a =0; a< trees; a++)
		{
			int position = in.nextInt();
			int height = in.nextInt();
			Tree n = new Tree(height, position);
			if(a == 0)
			{
			//	System.out.println(position + "!" + height);
				tot++;
				n.fellLeft();				
			}
			else if(!previous.fell && previous.p + previous.h < n.p)
			{
			//	System.out.println(position + "?" + height);
				tot++;
				previous.fellRight();
			}
			if(a != 0 && previous.endOccupy < n.p - n.h)
			{
				//System.out.println(position + "." + height);
				tot++;
				n.fellLeft();
			}
			previous = n;
		}
		if(!previous.fell)
			tot++;
		System.out.println(tot);
	}
}
class Tree
{
	int endOccupy;
	int h;
	int p;
	boolean fell;
	public Tree(int height, int pos)
	{
		h = height;
		p = pos;
		endOccupy = p;
		fell = false;
	}
	public int fellLeft()
	{
		endOccupy = p;
		fell = true;
		return p;
	}
	public int fellRight()
	{
		fell = true;
		endOccupy = p + h;
		return p + h;
	}
}