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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

/*
 * some cheeky quote
 */

public class Main
{
    FastScanner in;
    PrintWriter out;
    private final static int MIN = Integer.MIN_VALUE;

    public void solve() throws IOException
    {
        int n = in.nextInt();
        int position[] = new int[n];
        int height[] = new int[n];
        for (int i = 0; i < n; i++)
        {
            position[i] = in.nextInt();
            height[i] = in.nextInt();
        }

        //Start of dp//
        int dp[][] = new int[n][2];
        dp[0][0] = 1;
        dp[0][1] = 1 < n && position[0] + height[0] < position[1] ? 1 : MIN;
        for (int i = 1; i < dp.length; i++)
        {
            dp[i][0] = dp[i][1] = MIN;
            if (position[i - 1] < position[i] - height[i])
            {
                dp[i][0] = Math.max(dp[i][0], dp[i - 1][0] + 1);
            }
            if (position[i - 1] + height[i - 1] < position[i] - height[i])
            {
                dp[i][0] = Math.max(dp[i][0], dp[i - 1][1] + 1);
            }

            dp[i][0] = Math.max(dp[i][0], Math.max(dp[i - 1][0], dp[i - 1][1]));
            if (i == n - 1 || (i + 1 < n && position[i] + height[i] < position[i + 1]))
            {
                dp[i][1] = Math.max(dp[i][1], Math.max(dp[i - 1][1] + 1, dp[i - 1][0] + 1));
            }
        }
        //End of dp//
        System.out.println(Math.max(dp[n - 1][0], dp[n - 1][1]));


    }

    public void run()
    {
        try
        {
            in = new FastScanner();
            out = new PrintWriter(System.out);

            solve();

            out.close();
        } catch (IOException e)
        {
            e.printStackTrace();
        }
    }

    class FastScanner
    {
        BufferedReader br;
        StringTokenizer st;

        FastScanner()
        {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next()
        {
            while (st == null || !st.hasMoreTokens())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt()
        {
            return Integer.parseInt(next());
        }
    }

    public static void main(String[] arg)
    {
        new Main().run();
    }
}

