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.util.*;
import java.io.*;
import java.math.*;

public class Main {
	static class FastScanner {
		BufferedReader s;
		StringTokenizer st;

		public FastScanner(InputStream InputStream) {
			st = new StringTokenizer("");
			s = new BufferedReader(new InputStreamReader(InputStream));
		}

		public FastScanner(File f) throws FileNotFoundException {
			st = new StringTokenizer("");
			s = new BufferedReader(new FileReader(f));
		}

		public int nextInt() throws IOException {
			if (st.hasMoreTokens())
				return Integer.parseInt(st.nextToken());
			else {
				st = new StringTokenizer(s.readLine());
				return nextInt();
			}
		}

		public BigInteger big() throws IOException {
			if (st.hasMoreTokens())
				return new BigInteger(st.nextToken());
			else {
				st = new StringTokenizer(s.readLine());
				return big();
			}
		}

		public double nextDouble() throws IOException {
			if (st.hasMoreTokens())
				return Double.parseDouble(st.nextToken());
			else {
				st = new StringTokenizer(s.readLine());
				return nextDouble();
			}
		}

		public long nextLong() throws IOException {
			if (st.hasMoreTokens())
				return Long.parseLong(st.nextToken());
			else {
				st = new StringTokenizer(s.readLine());
				return nextLong();
			}
		}

		public String next() throws IOException {
			if (st.hasMoreTokens())
				return st.nextToken();
			else {
				st = new StringTokenizer(s.readLine());
				return next();
			}

		}

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

		public void close() throws IOException {
			s.close();
		}

	}
	
	public static void main(String[] args) throws java.lang.Exception {
		FastScanner in = new FastScanner(System.in);
		int n = in.nextInt();
		pair arr[] = new pair[n];
		for(int x = 0; x < n; x++) {
			arr[x] = new pair(in.nextInt(), in.nextInt());
		}
		Arrays.sort(arr);
		if(n<=2) {
			System.out.println(n);
			return;
		}
		int[] diff = new int[n - 1];
		for(int x = 1; x < n; x++)
			diff[x - 1] = arr[x].a - arr[x - 1].a - 1;
		int[] dp[] = new int[n][2];
		System.out.println(maxTree(diff, 1, arr, dp) + 2);
	}

	private static int maxTree(int[] diff, int i, pair[] arr, int[][] dp) {
		if(i == diff.length)
			return 0;
		maxTree(diff, i + 1, arr, dp);
		dp[i][0] = Math.max(dp[i + 1][0], dp[i + 1][1]) + (diff[i - 1] >= arr[i].b? 1 : 0);
		dp[i][1] = (diff[i] >= arr[i].b? (diff[i] >= arr[i].b + arr[i + 1].b ? 1 + Math.max(dp[i + 1][0], dp[i + 1][1]):1 + dp[i + 1][1]): Math.max(dp[i + 1][0], dp[i + 1][1]));
		return Math.max(dp[i][0], dp[i][1]);
	}

	static class pair implements Comparable<pair>{
		int a, b;
		pair(int a, int b) {
			this.a = a;
			this.b = b;
		}
		public int compareTo(pair obj) {
			return a - obj.a;
		}
	}
}