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.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author zodiacLeo
 */
public class Main
{
    public static void main(String[] args)
    {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC
    {
        public void solve(int testNumber, Scanner in, PrintWriter out)
        {
        /*
            //Greedy approach//
            int last = Integer.MIN_VALUE;
            int n = in.nextInt();
            int pos[] = new int[n];
            int h[] = new int[n];
            for (int i = 0; i < n; i++)
            {
                pos[i] = in.nextInt();
                h[i] = in.nextInt();
            }
            int count = 0;
            for (int i = 0; i < n; i++)
            {
                if (pos[i] - h[i] >= last)
                {
                    count++;
                    last = pos[i] + 1;
                }else
                {
                    last = pos[i] + 1;
                    if ((i == n - 1) || (pos[i] + h[i] < pos[i + 1]))
                    {
                        count++;
                        last = pos[i] + h[i] + 1;
                    }
                }
            }
            out.println(count);
        */


            //DP//
            int n = in.nextInt();
            int pos[] = new int[n];
            int height[] = new int[n];
            for (int i = 0; i < n; i++)
            {
                pos[i] = in.nextInt();
                height[i] = in.nextInt();
            }

        /*
        j == 0 -> left
        j == 1 -> right
         */

            int dp[][] = new int[n][2];
            for (int i = 0; i < n; i++)
            {
                if (i == 0)
                {
                    dp[i][0] = 1;
                    dp[i][1] = (i == n - 1 || pos[i] + height[i] < pos[i + 1]) ? 1 : 0;
                } else
                {
                    int max = Math.max(dp[i - 1][0], dp[i - 1][1]);
                    dp[i][0] = dp[i][1] = max;
                    if (pos[i] - height[i] > pos[i - 1])
                    {
                        dp[i][0] = Math.max(dp[i][0], dp[i - 1][0] + 1);
                    }
                    if (pos[i] - height[i] > pos[i - 1] + height[i - 1])
                    {
                        dp[i][0] = Math.max(dp[i][0], dp[i - 1][1] + 1);
                    }

                    if (i == n - 1 || pos[i] + height[i] < pos[i + 1])
                    {
                        dp[i][1]++;
                    }
                }
            }
            out.println(Math.max(dp[n - 1][0], dp[n - 1][1]));

        }

    }
}

