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

/*Author LAVLESH*/
import java.util.*;
import java.io.*;

public class solution {
	
	static class FastScanner{
		BufferedReader B;
		StringTokenizer st;
		public FastScanner(){
			st=new StringTokenizer("");
			B=new BufferedReader(new InputStreamReader(System.in));
		}
		
		public int nextInt() throws IOException{
			if(st.hasMoreTokens())
				return Integer.parseInt(st.nextToken());
			else{
				st = new StringTokenizer(B.readLine());
				return nextInt();
			}
			}
			
		public long nextLong() throws IOException{
			if(st.hasMoreTokens())
				return Long.parseLong(st.nextToken());
			else{
				st= new StringTokenizer(B.readLine());
				return nextLong();
			}
		}
			public double nextDouble() throws IOException{
				if(st.hasMoreTokens())
					return Double.parseDouble(st.nextToken());
				else{
					st = new StringTokenizer(B.readLine());
					return nextDouble();
				}
			}
		
		
	}

	
	public static void main(String args[])throws Exception
    {
     
     FastScanner in=new FastScanner();
      int n=in.nextInt();
      int []a=new int[n+1];
      int []b=new int[n+1];
      int i,cnt=0;
      for(i=1;i<=n;i++)
      {
    	  a[i]=in.nextInt();
    	  b[i]=in.nextInt();
      }
     if(n<=1)cnt=n;
     else{
      for(i=2;i<n;i++)
      {
    	  if(a[i]-b[i]>a[i-1]){ cnt++;}
    	  else if(a[i]+b[i]<a[i+1]-b[i+1]){cnt++;}
    	  else if(a[i]+b[i]<a[i+1])
    	  {
    		  a[i]=a[i]+b[i];
    		  b[i]=0;
    		  cnt++;
    	  }
    	  
      }}
     if(n>=2)cnt+=2;
     System.out.print(cnt);
  }
}

