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.Arrays;
import java.util.StringTokenizer;



public class knapsack {
	static int pos[];
	static int h[];
	static int n;
	static int memo[][];
	

	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		n=sc.nextInt();
	    pos=new int[n];
	    h=new int [n];
	    for(int i=0;i<n;i++) {
	    	pos[i]=sc.nextInt();
	    	h[i]=sc.nextInt();
	    }
	    int ans=2;
	    int idx=-1;
	    for(int i=1;i<n-1;i++) {
	    	if(idx==-1&&pos[i]-pos[i-1]-h[i]>0) {
	    		ans++;
	    	}
	    	
	    	else
	    		if(idx!=-1&&pos[i]-idx-h[i]>0) {
	    			ans++;
	    			idx=-1;
	    			}
	    		else
	    			if(pos[i+1]-pos[i]-h[i]>0) {
	    				ans++;
	    				idx=pos[i]+h[i];
	    				
	    			}
	    			else idx=-1;
	    }
	    System.out.println(n==1?1:ans);
	}
	static int dp(int idx,int state) {// state 1 stay    2 left      3 right
		if(idx>=n)return 0;
		if(memo[idx][state]!=-1)return memo[idx][state];
		int stay=dp(idx+1,1);
		int left;
		if(state==0||((state==1||state==2)&&pos[idx]-pos[idx-1]>h[idx])||(state==3&&pos[idx]-pos[idx-1]-h[idx-1]-h[idx]>0)) {
			left=1+dp(idx+1,2);
		}
		
		else {
			left=-(int)1e9;
		}
		int right=0;
		if((idx<n-1&&pos[idx]+h[idx]<pos[idx+1])||idx==n-1) {
			right=1+dp(idx+1,3);
		}
		else {
			right=-(int)1e9;
		}
		return memo[idx][state]= Math.max(stay, Math.max(left, right));
		
	}
	
	
	static class Scanner {

        BufferedReader br;
        StringTokenizer st;

        Scanner(InputStream system) {
            br = new BufferedReader(new InputStreamReader(system));
        }

        String next() throws IOException {
            while (st == null || !st.hasMoreTokens())
                st = new StringTokenizer(br.readLine());
            return st.nextToken();
        }

        int nextInt() throws IOException {
            return Integer.parseInt(next());
        }

        double nextDouble() throws IOException {
            return Double.parseDouble(next());
        }

        long nextLong() throws IOException {
            return Long.parseLong(next());
        }


	}

}

