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

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/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
import java.util.*;
import java.io.*;
/**
 *
 * @author MR
 */
public class Code {

    /**
     * @param args the command line arguments
     */
    static int n , y[][] ;
    static long x[][] ;
    static int ret( int i , long h , int st )
    {
        if ( i == n )
            return 0 ;
        if ( h == -1 )
            return 1 + ret( i + 1 , x[i][0] , 1 ) ;
        if ( y[i][st] != -1 )
            return y[i][st] ;
        int a = 0 , b = 0 , c = 0 ;
        if ( h >= x[i][0] )
            return -1000000000 ;
        if ( x[i][0] - x[i][1] > h )
            c = 1 + ret( i + 1 , x[i][0] , 1 ) ;
        a = Math.max(c, ret( i + 1 , x[i][0] , 0 )) ;
        b = 1 + ret( i + 1 , x[i][0] + x[i][1] , 2 ) ;
        return y[i][st] = Math.max(a, b) ;
    }
    public static void main(String[] args) {
        // TODO code application logic here
        LetsDoIt in = new LetsDoIt();
//        Scanner in = new Scanner(System.in) ;
//        FastReaderFile in = new FastReaderFile(new FileInputStream("fun.in")) ;
//        out = new PrintWriter(new BufferedOutputStream(new FileOutputStream("output.txt")), true) ;
        out = new PrintWriter(new BufferedOutputStream(System.out), true) ;
        n = in.nextInt() ;
        x = new long[n][2] ;
        y = new int[n][3] ;
        for ( int i = 0 ; i < n ; ++i )
        {
            x[i][0] = in.nextInt() ;
            x[i][1] = in.nextInt() ;
            Arrays.fill(y[i], -1) ;
        }
        out.println(ret( 0 , -1 , -1)) ;
    }
    static long nCk( long n, long k )
    {
	    if (k > n) return 0;
	    if (k * 2 > n) k = n-k;
	    if (k == 0) return 1;
	
	    long result = n;
	    for( long i = 2; i <= k; ++i ) {
	        result *= (n-i+1);
	        result /= i;
	    }
	    return result;
}
    static  boolean isPrime( long n)
    {
        if (n < 2)  return false;
        if (n < 4)  return true;
        
        if (n%2 == 0 || n%3 == 0) return false;

        for (long i = 5 ; i * i <= n ; i = i + 6 )
            if ( n % i == 0 || n % ( i + 2 ) == 0)
                return false ;

        return true;
    }
    static long gcd(long a, long b) 
    {
        return b == 0 ? (a < 0 ? -a : a) : gcd(b, a % b);
    }
    static long lcm(long a, long b)
    {
        long lcm = (a / gcd(a, b)) * b;
        return lcm > 0 ? lcm : -lcm ;
    }
	public static class FastReaderFile
    {
        BufferedReader br;
        StringTokenizer st;
        public FastReaderFile(InputStream in)
        {
            br = new BufferedReader(new
            InputStreamReader(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 class LetsDoIt
    {
        BufferedReader br;
        StringTokenizer st;

        public LetsDoIt()
        {
            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 PrintWriter out;
}