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.awt.Point;
import java.util.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.*;
import java.util.*;

public class Main {
	//////
	static class FastReader {
		BufferedReader br;
		StringTokenizer st;

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

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

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

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

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
	}

	//////
	public static long modularExponentiation(long x, long n, long M) {
		long result = 1;
		while (n > 0) {
			if (n % 2 == 1)
				result = (result * x) % M;
			x = (x * x) % M;
			n = n / 2;
		}
		return result;
	}

	public static long modularExponentiation1(long x, long n) {
		long result = 1;
		while (n > 0) {
			if (n % 2 == 1)
				result = (result * x);
			x = (x * x);
			n = n / 2;
		}
		return result;
	}

	/////

	static public int fun(int num) {
		int prod = 1;
		while (num > 0) {
			if (num % 10 != 0) {
				prod = prod * (num % 10);
			}
			num = num / 10;
		}
		return prod;
	}

	public static boolean dfs(int x, int find, boolean[] visited, int[][] matrix) {

		boolean ans = false;
		if (x == find) {
			ans = true;
			return true;
		}
		for (int i = 0; i < 26; i++) {
			if (visited[i] == false && matrix[x][i] == 1) {
				visited[i] = true;
				ans = ans || dfs(i, find, visited, matrix);
			}
		}

		return ans;
	}

	static int lis(int arr[], int n, int k, int b) {
		int lis[] = new int[n];
		int i, j, max = 0;

		/* Initialize LIS values for all indexes */
		for (i = 0; i < n; i++)
			lis[i] = 1;

		/* Compute optimized LIS values in bottom up manner */
		for (i = 1; i < n; i++)
			for (j = 0; j < i; j++)
				if (arr[i] >= k * arr[j] + b && lis[i] < lis[j] + 1)
					lis[i] = lis[j] + 1;

		/* Pick maximum of all LIS values */
		for (i = 0; i < n; i++)
			if (max < lis[i])
				max = lis[i];

		return max;
	}

	public static void main(String[] args) throws IOException {

		FastReader scan = new FastReader();
		PrintWriter pw = new PrintWriter(System.out);

		int N=scan.nextInt();
		int[] A=new int[N];
		int[] H=new int[N];
		for(int i=0;i<N;i++){
			A[i]=scan.nextInt();
			H[i]=scan.nextInt();
		}
		
		int count=2;
		
		for(int i=1;i<N-1;i++){
			if(A[i]-A[i-1]>H[i]){
				count++;
			}else if(A[i+1]-A[i]>H[i]){
				count++;
				A[i]=A[i]+H[i];
			}
		}
		
		if(N==1){
			System.out.println("1");
			return;
		}
		System.out.println(count);
				
	}
}