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.*;
import java.text.*;
public class div303{
	static int dp[][];
	static int arr[][];
	public static void main(String[] args) throws Exception
    {
	   //new FileInputStream("input.txt");
		//new FileOutputStream("output.txt")
		InputReader in = new InputReader(System.in);
		OutputWriter out = new OutputWriter(System.out);
		int n =in.ri();
		arr=new int[n][2];
		for(int i=0;i<n;i++){
			arr[i][0]=in.ri();
			arr[i][1]=in.ri();
		}
		dp=new int[n-1][2];
		int val=Math.max(solve(n-2,0)+1,solve(n-2,1));
		out.pl(val);
		out.close();
	}
	
	public static int solve(int index,int dir){  //dir==0(same state), dir==1(fallen left)
		if(index<0)return 0;
		if(index==0)return 1;
		if(dp[index][dir]>0)return dp[index][dir];
		int incl_le,incl_ri,excl;
		incl_le=incl_ri=excl=0;
		if(dir==1&&arr[index][0]+arr[index][1]<arr[index+1][0]-arr[index+1][1])
			incl_ri=solve(index-1,0)+1;
		if(dir==0&&arr[index][0]+arr[index][1]<arr[index+1][0])
			incl_ri=solve(index-1,0)+1;	
		excl=solve(index-1,0);
		if(arr[index-1][0]<arr[index][0]-arr[index][1])
			incl_le=solve(index-1,1)+1;
		dp[index][dir]=Math.max(excl,Math.max(incl_le,incl_ri));
		return dp[index][dir];
		
	}
private static class InputReader
	{
		private InputStream stream;
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;
		private SpaceCharFilter filter;
		 
		public InputReader(InputStream stream)
		{
			this.stream = stream;
		}
 
		public int read()
		{
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars)
			{
				curChar = 0;
				try
				{
					numChars = stream.read(buf);
				} catch (IOException e)
				{
					throw new InputMismatchException();
				}
				if (numChars <= 0)
				return -1;
			}
			return buf[curChar++];
		}
		
		public String rs()
        {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do
            {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        } 
        
		public int ri()
		{
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-')
			{
				sgn = -1;
				c = read();
			}
			int res = 0;
			do
			{
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
		
		public double rd() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            double res = 0;
            while (!isSpaceChar(c) && c != '.') {
                if (c == 'e' || c == 'E')
                    return res * Math.pow(10, ri());
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            }
            if (c == '.') {
                c = read();
                double m = 1;
                while (!isSpaceChar(c)) {
                    if (c == 'e' || c == 'E')
                        return res * Math.pow(10, ri());
                    if (c < '0' || c > '9')
                        throw new InputMismatchException();
                    m /= 10;
                    res += (c - '0') * m;
                    c = read();
                }
            }
            return res * sgn;
        }
		
		public long rl() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }
        
		public boolean isSpaceChar(int c)
		{
			if (filter != null)
				return filter.isSpaceChar(c);
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}
 
		
 
		public interface SpaceCharFilter
		{
			public boolean isSpaceChar(int ch);
		}
	}
 
	private static class OutputWriter
	{
		private final PrintWriter writer;
 
		public OutputWriter(OutputStream outputStream)
		{
			writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
		}
 
		public OutputWriter(Writer writer)
		{
			this.writer = new PrintWriter(writer);
		}
 		public void print(Object... objects)
		{
			for (int i = 0; i < objects.length; i++)
			{
				if (i != 0)
				writer.print(' ');
				writer.print(objects[i]);
			}
		}
		
		public void pf(double n)
		{
			writer.printf("%.2f%n", n);
		}
		public void pl(Object... objects)
		{
			print(objects);
			writer.println();
		}
 
		public void close()
		{
			writer.close();
		}
 
		public void flush()
		{
			writer.flush();
		}
 
	}
}
