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.*;
import java.math.BigInteger;

public class E {

	static boolean[] vis;
	static int[] cat;
	static int n;
	static ArrayList<Integer>[] a;
	static pair[] p;

	static int memo[][];

	public static int dp(int idx, int s) {
		if (idx == n)
			return 0;
		if (memo[s][idx] != -1)
			return memo[s][idx];
		int r = -1;
		int l = -1;
		int c = dp(idx + 1, 0);
		if (s == 0) {
			if (idx == 0 || p[idx].x - p[idx].y > p[idx - 1].x)
				l = 1 + dp(idx + 1, 1);
			else if (idx == n - 1 || p[idx].x + p[idx].y < p[idx + 1].x)
				r = 1 + dp(idx + 1, 2);

		} else if (s == 1) {
			if (p[idx].x - p[idx].y > p[idx - 1].x)
				l = 1 + dp(idx + 1, 1);
			else if (idx == n - 1 || p[idx].x + p[idx].y < p[idx + 1].x)
				r = 1 + dp(idx + 1, 2);
		} else {
			if (p[idx].x - p[idx].y > p[idx - 1].x + p[idx - 1].y)
				l = 1 + dp(idx + 1, 1);
			else if (idx == n - 1 || p[idx].x + p[idx].y < p[idx + 1].x)
				r = 1 + dp(idx + 1, 2);
		}
		return memo[s][idx] = Math.max(Math.max(r, l), c);
	}

	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter pw = new PrintWriter(System.out);
		Scanner sc = new Scanner(System.in);
		n = Integer.parseInt(br.readLine());
		p = new pair[n];
		for (int i = 0; i < n; i++) {
			StringTokenizer st = new StringTokenizer(br.readLine());
			p[i] = new pair(Integer.parseInt(st.nextToken()), Integer.parseInt(st.nextToken()));
		}
		memo = new int[3][n];
		Arrays.fill(memo[0], -1);
		Arrays.fill(memo[1], -1);
		Arrays.fill(memo[2], -1);

		pw.println(dp(0, 0));
		pw.flush();
		pw.close();
	}

	static class pair implements Comparable<pair> {
		int x;
		int y;

		public pair(int d, int u) {
			x = d;
			y = u;
		}

		@Override
		public int compareTo(pair o) {
			// TODO Auto-generated method stub
			if (x == o.x)
				return y - o.y;
			return x - o.x;
		}

	}
}
