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.Arrays;
import java.util.StringTokenizer;

public class Main{

static final InputStream in=System.in;
static final PrintWriter out=new PrintWriter(System.out);
static int[][] dp=new int[100000][3];

public static class Range{
private static int[] lrange=new int[100000];
private static int[] rrange=new int[100000];
public static void change(int n,int x,int y){
if(y<x) return;
lrange[n]=x; rrange[n]=y;
}
public static boolean isInRange(int t,int lx,int rx){
if(lx>rx) return false;
if((lrange[t-1]>rx||rrange[t-1]<lx)&&(lrange[t+1]>rx||rrange[t+1]<lx)) return false;
return true;
}
}

public static void main(String[] args) throws IOException{
BufferedReader br=new BufferedReader(new InputStreamReader(in));
String line="";
StringTokenizer st;
while((line=br.readLine())!=null&&!line.isEmpty()){
int n=Integer.parseInt(line);
int[] x=new int[n];
int[] h=new int[n];
Range r=new Range();
for(int i=0;i<n;i++){
Arrays.fill(dp[i],-1);
st=new StringTokenizer(br.readLine());
x[i]=Integer.parseInt(st.nextToken());
h[i]=Integer.parseInt(st.nextToken());
r.change(i,x[i],x[i]);
}
if(n<=1) out.println(n);
else out.println(dfs(1,0,x,h,r)+2);
}
out.flush();
}

public static int dfs(int now,int cond,final int[] x,final int[] h,Range r){
if(now==x.length-1) return 0;
if(dp[now][cond]>=0) return dp[now][cond];
int cr,cl,cn;
cr=cl=Integer.MIN_VALUE;
int nx=x[now];
int nh=h[now];
if(!r.isInRange(now,nx-nh,nx)){
r.change(now,nx-nh,nx);
cl=dfs(now+1,1,x,h,r)+1;
r.change(now,nx,nx);
}
if(!r.isInRange(now,nx,nx+nh)){
r.change(now,nx,nx+nh);
cr=dfs(now+1,2,x,h,r)+1;
r.change(now,nx,nx);
}
cn=dfs(now+1,0,x,h,r);
return dp[now][cond]=Math.max(Math.max(cr,cl),cn);
}
}