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 woodcutters 
{
	
	public static void main(String args[])throws IOException
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out = new PrintWriter(System.out);
		
		int n = ip(br.readLine());
		int [] x = new int [n+1];
		int [] h = new int [n+1];
		
		for (int i = 1; i<=n; i++)
		{
			String [] tokens = br.readLine().split(" ");
			x[i] = ip(tokens[0]);
			h[i] = ip(tokens[1]);
		}
		
		int [][] dp = new int [n+1][3];
		
		if (n <= 2)
		{out.println(n);out.close(); out.flush(); return;}
		
		// 0 for stay and 1 for left and 2 for right
		
		dp[1][0] = 0;
		dp[1][1] = 1;
		
		if (x[1]+h[1] < x[2])
			dp[1][2] = 1;
	
		for (int i = 2; i <= n; i++)
		{
			// if current stays up
			dp[i][0] = Math.max(dp[i-1][0], Math.max(dp[i-1][1], dp[i-1][2]));
			// if current falls right 
			
			// if current falls left
			int a = 0;
			int b = 0;
			int c = 0;
			if (x[i]-h[i] > x[i-1])
			{
				c = dp[i-1][0] + 1;
				b = dp[i-1][1] + 1;
			}
			if (x[i]-h[i] > x[i-1]+h[i-1])
				a = dp[i-1][2] + 1;
			dp[i][1] = Math.max(a, Math.max(b,  c));
			
			if (i == n)
				{dp[i][2] =  Math.max(dp[i-1][0]+1, Math.max(dp[i-1][1]+1, dp[i-1][2]+1)); break;}
			if (x[i]+h[i] < x[i+1])
				dp[i][2] = Math.max(dp[i-1][0]+1, Math.max(dp[i-1][1]+1, dp[i-1][2]+1));
			
		}
		
		out.println(Math.max(dp[n][1], dp[n][2]));
		out.close();
		out.flush();
	}
	

	static int ip(String s)
	{
		return Integer.parseInt(s);
	}
}
