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.*;
import java.io.*;
public class Woodcutters
{
	static int[][][] memoize;
	static tree[] arr;
	public static void main(String args[]) throws Exception
	{
		BufferedReader f=new BufferedReader(new InputStreamReader(System.in));
		// BufferedReader f=new BufferedReader(new FileReader("Woodcutters.in"));
		int runs=Integer.parseInt(f.readLine());
		arr=new tree[runs];
		for(int x=0;x<runs;x++)
		{
			StringTokenizer st=new StringTokenizer(f.readLine());
			arr[x]=new tree(Integer.parseInt(st.nextToken()),Integer.parseInt(st.nextToken()));
		}
		memoize=new int[runs][3][3];
		for(int a=0;a<runs;a++)
			for(int b=0;b<3;b++)
				for(int c=0;c<3;c++)
					memoize[a][b][c]=-1;
		System.out.println(Math.max(solve(0,0,2),solve(0,1,2)));
	}
	public static int solve(int pos,int cur_dir,int prev_dir)
	{
		if(pos==arr.length) return 0;
		// if(cur_dir==0&&pos!=0)
			// System.out.println(pos+" "+cur_dir+" "+prev_dir+" "+(arr[pos].pos-arr[pos].height)+" "+(arr[pos-1].pos+arr[pos-1].height));
		if(cur_dir==0&&pos!=0&&(arr[pos].pos-arr[pos].height<=arr[pos-1].pos||(prev_dir==1&&arr[pos].pos-arr[pos].height<=arr[pos-1].pos+arr[pos-1].height))) return Integer.MIN_VALUE;
		if(cur_dir==1&&pos!=arr.length-1&&arr[pos].pos+arr[pos].height>=arr[pos+1].pos) return Integer.MIN_VALUE;
		if(memoize[pos][cur_dir][prev_dir]!=-1) return memoize[pos][cur_dir][prev_dir];
		// System.out.println("pos: "+pos+" cur_dir: "+cur_dir);
		//try cutting left, right, and not cutting at all
		int one=solve(pos+1,0,cur_dir)+1;
		int two=solve(pos+1,1,cur_dir)+1;
		int three=solve(pos+1,2,cur_dir);
		// System.out.println("pos: "+pos+" cur_dir: "+cur_dir+" prev_dir: "+prev_dir+" one: "+one+" two: "+two+" three: "+three);
		return memoize[pos][cur_dir][prev_dir]=Math.max(one,Math.max(two,three));
	}
}
class tree
{
	int pos,height;
	public tree(int a,int b)
	{
		pos=a;
		height=b;
	}
}