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.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.StringTokenizer;

public class Main {

    public static void main(String[] args) throws IOException {
        FastReader fr = new FastReader();
        FastWriter fw = new FastWriter();
        int n = fr.nextInt();
        int x[] = new int[n + 1];
        int h[] = new int[n + 1];
        for (int i = 1; i <= n; i++) {
            x[i] = fr.nextInt();
            h[i] = fr.nextInt();
        }
        int dp[][] = new int[n + 1][3]; // 0 = don't cut, 1 = cut on left, 2 = cut on right
        x[0] = Integer.MIN_VALUE;
        for (int i = 1; i <= n; i++) {
            dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1]);
            if (x[i - 1] + h[i - 1] < x[i]) {
                dp[i][0] = Math.max(dp[i][0], dp[i - 1][2]);
            }
            if (x[i] - h[i] > x[i - 1]) {
                dp[i][1] = Math.max(dp[i - 1][0], dp[i - 1][1]);
                if (x[i - 1] + h[i - 1] < x[i] - h[i]) {
                    dp[i][1] = Math.max(dp[i][1], dp[i - 1][2]);
                }
                dp[i][1]++;
            }
            dp[i][2] = 1 + dp[i][0];
        }
        fw.println(Math.max(dp[n][0], Math.max(dp[n][1], dp[n][2])));
    }

}


class FastReader {
    public FastReader() {
    }

    public FastReader(String fileName) throws FileNotFoundException {
        this.br = new BufferedReader(new FileReader(fileName));
    }

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st;

    String nextString() throws IOException {
        if (st == null || !st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }

    int nextInt() throws IOException {
        return Integer.parseInt(nextString());
    }

    long nextLong() throws IOException {
        return Long.parseLong(nextString());
    }

    double nextDouble() throws IOException {
        return Double.parseDouble(nextString());
    }
}

class FastWriter {
    public FastWriter() {
    }

    public FastWriter(String fileName) throws IOException {
        this.bw = new BufferedWriter(new FileWriter(fileName));
    }

    BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

    void print(Object o) throws IOException {
        bw.write(o.toString());
        bw.flush();
    }

    void println(Object o) throws IOException {
        print(o.toString() + "\n");
    }

    void printSp(Object o) throws IOException {
        print(o.toString() + " ");
    }
}