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.Arrays;
import java.util.StringTokenizer;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

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

    static class WoodCutters {
        int n;
        long[] x;
        long[] h;
        int[][] memo;

        int f(int i, int dir) {
            if (i == n - 1) return 1;
            if (memo[dir][i] != -1) return memo[dir][i];

            int ans = 0;

            if (i == 0) {
                ans = Math.max(ans, f(i + 1, 0) + 1);
            } else {
                switch (dir) {
                    case 0:
                        if (x[i - 1] < x[i] - h[i])
                            ans = Math.max(ans, f(i + 1, 0) + 1);
                        if (i + 1 < n && x[i] + h[i] < x[i + 1])
                            ans = Math.max(ans, f(i + 1, 1) + 1);
                        break;
                    case 1:
                        if (x[i - 1] + h[i - 1] < x[i] - h[i])
                            ans = Math.max(ans, f(i + 1, 0) + 1);
                        if (i + 1 < n && x[i] + h[i] < x[i + 1])
                            ans = Math.max(ans, f(i + 1, 1) + 1);
                        break;
                }
            }
            ans = Math.max(ans, f(i + 1, dir));
            ans = Math.max(ans, f(i + 1, 1 - dir));

            return memo[dir][i] = ans;
        }

        public void solve(int testNumber, FastReader fs, PrintWriter pw) {
            n = fs.nextInt();
            x = new long[n];
            h = new long[n];
            memo = new int[2][n];

            for (int i = 0; i < n; i++) {
                x[i] = fs.nextLong();
                h[i] = fs.nextLong();
            }

            for (int i = 0; i < 2; i++) Arrays.fill(memo[i], -1);

            int right = f(0, 0);
            int left = f(0, 1);

            pw.println(Math.max(left, right));
        }

    }

    static class FastReader {
        BufferedReader bf;
        StringTokenizer st;

        public FastReader(InputStream is) {
            bf = new BufferedReader(new InputStreamReader(is));
            st = null;
        }

        public String next() {
            try {
                while (st == null || !st.hasMoreTokens()) {
                    String line = bf.readLine();
                    if (line == null) return null;
                    st = new StringTokenizer(line);
                }
            } catch (Exception e) {
            }

            return st.nextToken();
        }

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

        public long nextLong() {
            return Long.parseLong(next());
        }

    }
}

