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 C545 {
	
	public static void main(String[] args) throws Exception {

		int n = Integer.parseInt(in.readLine());

		int[] h = new int[n];
		int[] x = new int[n];

		for (int i = 0; i < n; i++) {
			st = new StringTokenizer(in.readLine());
			x[i] = i();
			h[i] = i();
		}

		int[][] dp = new int[n][3];
		int MIN = -100000;

		dp[0][0] = 0;
		dp[0][1] = 1;
		dp[0][2] = n > 1 ? x[0] + h[0] < x[1] ? 1 : 0 : 1;

		for (int i = 1; i < n; i++) {
			dp[i][0] = max(dp[i - 1][0], dp[i - 1][1], dp[i - 1][2]);

			int l = x[i - 1] < x[i] - h[i] ? 1 : MIN;
			int l2 = x[i - 1] + h[i - 1] < x[i] - h[i] ? 1 : MIN;
			int r = i == n - 1 ? 1 : x[i] + h[i] < x[i + 1] ? 1 : MIN;

			dp[i][1] = max(dp[i - 1][0] + l, dp[i - 1][1] + l, dp[i - 1][2] + l2);

			dp[i][2] = r + dp[i][0];
		}	

		out.println(max(dp[n - 1][0], dp[n - 1][1], dp[n - 1][2]));

		out.close();
	}

	public static int max(int a, int b, int c) {
		return Math.max(a, Math.max(b, c));
	}

	static BufferedReader in;
	static StringTokenizer st;
	static PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
	static {
		try {
			in = new BufferedReader(new FileReader("cf.in"));
		} catch (Exception e) {
			in = new BufferedReader(new InputStreamReader(System.in));
		}
	}
	static int i() {return Integer.parseInt(st.nextToken());}
	static double d() {return Double.parseDouble(st.nextToken());}
	static String s() {return st.nextToken();}
	static long l() {return Long.parseLong(st.nextToken());}
}
