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;

//not greeeeedy

public class Woodcutters {

	static int n , memo[][] , x[],h[];
	//0 --> last is left
	//1 --> last did not fall
	//2 --> last is right


	static int INF = -((int)(1e9)+10);
	static int solve(int i , int state)
	{
		if(i == n)
			return 0;

		if(memo[i][state] != -1)
			return memo[i][state];

		int last = -1;
		if(i == 0)
			last = INF;
		else
		{
			if(state == 0 || state == 1)
				last = x[i-1];
			else
				last = x[i-1]+h[i-1];
		}
		int ans  = 0;
		if(x[i]-h[i]>last)														 //try left
			ans = Math.max(ans, 1+solve(i+1,0));
		ans = Math.max(ans, solve(i+1,1)); 										 //try not to fall it
		if(i==n-1 || x[i]+h[i]<x[i+1]) 											 //try right
			ans = Math.max(ans , 1+solve(i+1,2));

		return memo[i][state] = ans;
	}

	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		n = sc.nextInt();

		x = new int[n];
		h = new int[n];
		for(int i=0;i<n;i++)
		{
			x[i] = sc.nextInt();
			h[i] = sc.nextInt();
		}
		memo = new int[n+1][4];
		for (int i = 0; i < memo.length; i++) {
			Arrays.fill(memo[i], -1);
		}
		int cc = n-10;
		while(cc>0)
		{
			solve(cc,0);
			solve(cc,1);
			solve(cc,2);
			cc-=1000;
		}
		
		System.out.println(solve(0,0));
	}
	static class Scanner 
	{
		StringTokenizer st;
		BufferedReader br;

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

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

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

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

		public String nextLine() throws IOException {return br.readLine();}

		public double nextDouble() throws IOException
		{
			String x = next();
			StringBuilder sb = new StringBuilder("0");
			double res = 0, f = 1;
			boolean dec = false, neg = false;
			int start = 0;
			if(x.charAt(0) == '-')
			{
				neg = true;
				start++;
			}
			for(int i = start; i < x.length(); i++)
				if(x.charAt(i) == '.')
				{
					res = Long.parseLong(sb.toString());
					sb = new StringBuilder("0");
					dec = true;
				}
				else
				{
					sb.append(x.charAt(i));
					if(dec)
						f *= 10;
				}
			res += Long.parseLong(sb.toString()) / f;
			return res * (neg?-1:1);	
		}

		public boolean ready() throws IOException {return br.ready();}
	}

}
