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.*;
import java.util.*;

public class Woodcutters {
    
    static class Tree {
        int x, h;
        Tree(int x, int h) {
            this.x = x;
            this.h = h;
        }
    }
    
    static Integer[][] dp;
    
    static int dp(int cur, int prev, Tree[] trees) {
        if (cur == trees.length) {
            return 0;
        }
        
        if (dp[cur][prev] != null) {
            return dp[cur][prev];
        }
        if (cur == 0) {
            return dp[cur][prev] = Math.max(Math.max(1 + dp(cur + 1, 0, trees), dp(cur + 1, 1, trees)), 1 + dp(cur + 1, 2, trees));
        } else {
            int left = prev == 2 ? trees[cur - 1].x + trees[cur - 1].h : trees[cur - 1].x;
            int right = cur < trees.length - 1 ? trees[cur + 1].x : Integer.MAX_VALUE;
            int ans = 0;
            if (left < trees[cur].x - trees[cur].h) {
                ans = Math.max(ans, 1 + dp(cur + 1, 0, trees));
            }
            ans = Math.max(ans, dp(cur + 1, 1, trees));
            if (right > trees[cur].x + trees[cur].h) {
                ans = Math.max(ans, 1 + dp(cur + 1, 2, trees));
            }
            return dp[cur][prev] = ans;
        }
    }
    
    public static void main(String[] args) {
        InputReader in = new InputReader(System.in);
        
        int N = in.nextInt();
        Tree[] trees = new Tree[N];
        for (int i = 0; i < N; ++i) {
            int x = in.nextInt();
            int h = in.nextInt();
            trees[i] = new Tree(x, h);
        }
        
        dp = new Integer[N + 1][3];
        int ans = dp(0, 0, trees);
        
        System.out.println(ans);
    }
    

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream));
            tokenizer = new StringTokenizer("");
        }

        public String next() {
            try {
                while (!tokenizer.hasMoreTokens())
                    tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            
            return tokenizer.nextToken();
        }
        
        public String nextLine() {
            String line = null;
            try {
                tokenizer = new StringTokenizer("");
                line =  reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            return line;
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }
        
        public double nextDouble() {
            return Double.parseDouble(next());
        }
        
        public long nextLong() {
            return Long.parseLong(next());
        }
        
        boolean hasNext() {
            while (!tokenizer.hasMoreTokens()) {
                String line = nextLine();
                if (line == null) return false;
                tokenizer = new StringTokenizer(line);
            }
            return true;
        }
    }
}
