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.math.BigInteger;
import java.util.ArrayList;
import java.util.StringTokenizer;

/**
 * Created by yujiahao on 5/9/16.
 */
public class cf_303_c {
    private FastScanner in;
    private PrintWriter out;

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

        /*
        int res = 2;
        boolean flag = false;
        for (int i=1; i<n-1; i++){
            if (x[i]-x[i-1]>h[i] && flag==false || x[i]-x[i-1]-h[i-1]>=h[i] && flag == true){
                res++;
                flag = false;
            }else if (x[i+1]-x[i] > h[i]){
                res++;
                flag = true;
            }
        }
        */

        int res = 0;
        if (n==2){
            out.print("2");
            return;
        }else if (n==1){
            out.print("1");
            return;
        }
        res = 2;

        long[] a = new long[n];
        int j = 0;
        a[0] = x[0];

        for (int i=1; i<n-1; i++){
            if (x[i]-x[i-1]>h[i] && x[i]-h[i]>a[j]){
                res ++;
                a[++j] = x[i];
            }else if (x[i+1]-x[i]>h[i]){
                res ++;
                a[++j] = x[i]+h[i];
            }
        }


        out.print(res);
    }


    public void run() {
        try {
            in = new FastScanner();
            out = new PrintWriter(System.out);
            solve();
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private class FastScanner {
        private BufferedReader br;
        private StringTokenizer st;

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

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

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

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

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public BigInteger nextBigInteger() { return new BigInteger(next());}

    }

    public static void main(String[] arg) {
        new cf_303_c().run();
    }
}
