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

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author Ivan
 */
public class thirdProblemGreedy {

    static int whereFit(int[][] treeInfo,int currTree)
    {
        //System.out.println(treeInfo[currTree][0]+" "+treeInfo[currTree][1]+" "+treeInfo[currTree][2]);
        boolean canLeft=false,canRight=false;
        if((treeInfo[currTree-1][2]==1||treeInfo[currTree-1][2]==0)&&((treeInfo[currTree][0]-treeInfo[currTree][1])>treeInfo[currTree-1][0]))
            canLeft=true;
        if(treeInfo[currTree-1][2]==2&&((treeInfo[currTree][0]-treeInfo[currTree][1])>(treeInfo[currTree-1][0]+treeInfo[currTree-1][1])))
            canLeft=true;
        if(((treeInfo[currTree][0]+treeInfo[currTree][1])<treeInfo[currTree+1][0]))
            canRight=true;
        if(canLeft&&canRight)
            return 3;
        if(canLeft)
            return 1;
        if(canRight)
            return 2;
        return 0;
            
    }
    public static void main(String[] args) throws IOException {
        Reader.init(System.in);
        int trees=Reader.nextInt();
        int[][] treeInfo=new int[trees][3];
        for(int i=0;i<trees;i++)
        {
            treeInfo[i][0]=Reader.nextInt();
            treeInfo[i][1]=Reader.nextInt();
            treeInfo[i][2]=0;
        }
        
        treeInfo[0][2]=1;
        treeInfo[trees-1][2]=2;
        int treeCount=2;
        int whereFit=0;
        
        for(int i=1;i<trees-1;i++)
        {
            whereFit=whereFit(treeInfo,i);
            if(whereFit==1||whereFit==3)
            {
                treeInfo[i][2]=1;
                treeCount++;
            }
            if(whereFit==2)
            {
                treeInfo[i][2]=2;
                treeCount++;
            }
    }
    
        if(trees==1)
            treeCount=1;
        System.out.println(treeCount);
       // for(int i=0;i<trees;i++)
       //     System.out.print(treeInfo[i][2]+" ");
    
}
}


class Reader {
    static BufferedReader reader;
    static StringTokenizer tokenizer;

    /** call this method to initialize reader for InputStream */
    static void init(InputStream input) {
        reader = new BufferedReader(
                     new InputStreamReader(input) );
        tokenizer = new StringTokenizer("");
    }

    /** get next word */
    static String next() throws IOException {
        while ( ! tokenizer.hasMoreTokens() ) {
            //TODO add check for eof if necessary
            tokenizer = new StringTokenizer(
                   reader.readLine() );
        }
        return tokenizer.nextToken();
    }

    static int nextInt() throws IOException {
        return Integer.parseInt( next() );
    }
	
    static double nextDouble() throws IOException {
        return Double.parseDouble( next() );
    }
}