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

/**
 * Created by ankeet on 12/28/16.
 */
import java.io.*;
import java.util.*;

public class C545 {

    static FastReader in = null;
    static PrintWriter out = null;

    public static void solve()
    {
        int n = in.nextInt();
        long[] x = new long[n];
        long[] h = new long[n];
        for(int i=0; i<n; i++){
            x[i] = in.nextInt();
            h[i] = in.nextInt();
        }
        if(n == 1){
            out.println(1);
            return;
        }
        // dp[i][0] = max # of trees falling using trees up to i, such that ith tree did not fall to right
        // dp[i][1] = max # of trees falling, ith tree did fall to right
        int[][] dp = new int[n][2];

        dp[0][0] = 1;
        dp[0][1] = x[0] + h[0] < x[1] ? 1 : 0;

        for(int i=1; i<n; i++){

            dp[i][0] = Math.max(dp[i-1][0], dp[i-1][1]);
            if(x[i] - h[i] > x[i-1]) dp[i][0] = Math.max(dp[i][0], dp[i-1][0] + 1);
            if(x[i] - h[i] > x[i-1] + h[i-1]) dp[i][0] = Math.max(dp[i][0], dp[i-1][1] + 1);

            if(i == n-1){
                dp[i][1] = Math.max(dp[i-1][0], dp[i-1][1]) + 1;
            }
            else{
                dp[i][1] = (x[i] + h[i] < x[i+1]) ? Math.max(dp[i-1][0], dp[i-1][1]) + 1 : 0;
            }
        }

        out.println(Math.max(dp[n-1][0], dp[n-1][1]));
    }

    public static void main(String[] args)
    {
        in = new FastReader(System.in);
        out = new PrintWriter(System.out);
        solve();
        out.flush();
        out.close();

    }

    static class FastReader {

        BufferedReader read;
        StringTokenizer tokenizer;

        public FastReader(InputStream in)
        {
            read = new BufferedReader(new InputStreamReader(in));
        }

        public String next()
        {
            while(tokenizer == null || !tokenizer.hasMoreTokens())
            {
                try{
                    tokenizer = new StringTokenizer(read.readLine());
                }catch(Exception e){
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }
        public String nextLine(){

            try
            {
                return read.readLine();
            }
            catch(Exception e)
            {
                throw new RuntimeException(e);
            }
        }
        public int nextInt()
        {
            return Integer.parseInt(next());
        }
        public long nextLong()
        {
            return Long.parseLong(next());
        }
        public double nextDouble()
        {
            return Double.parseDouble(next());
        }

        public int[] nextIntArr(int n)
        {
            int[] a = new int[n];
            for(int i=0; i<n; ++i)
            {
                a[i] = nextInt();
            }
            return a;
        }

        public long[] nextLongArr(int n)
        {
            long[] a = new long[n];
            for(int i=0; i<n; ++i)
            {
                a[i] = nextLong();
            }
            return a;
        }
    }


}


