import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;
import java.util.*;
 
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        solve(in, out);
        out.close();
    }

    class Node{
        int v;
        Node next;
        Node(int v){
            this.v=v;
            next=null;
        }
    }

    public static void solve(InputReader sc, PrintWriter pw) {
        int i,j=0;
        int t=1;
        // int t=sc.nextInt();
        u:while(t-->0){
            int n=sc.nextInt();
            long x[]=new long[n];
            long l[]=new long[n];
            Pair a[]=new Pair[n];
            for(i=0;i<n;i++){
                x[i]=sc.nextInt();
                l[i]=sc.nextInt();
                a[i]=new Pair(x[i]-l[i],x[i]+l[i]);
            }
            Arrays.sort(a);
            // for(i=0;i<n;i++){
            //     pw.println("# "+a[i].a+" "+a[i].b);
            // }
            long c=1;
            long till=a[0].b;
            for(i=1;i<n;i++){
                // pw.println(a[i].b+" "+till);
                if(a[i].a>=till){
                    till=a[i].b;
                    c++;
                }
            }
            pw.println(c);
        }
    }

    static class Pair implements Comparable<Pair>{
        long a;long b;
        Pair(long a,long b){
            this.a=a;
            this.b=b;
            //this.z=z;
        }   
        public int compareTo(Pair p){
            if(b>=p.b)
                return 1;
            if(b<p.b)
                return -1;
            return (a-p.a>=0)?1:-1;
        }
    }

    static boolean isPrime(int n) { 
        if (n <= 1) 
            return false; 
        if (n <= 3) 
            return true; 
        if (n % 2 == 0 || n % 3 == 0) 
            return false; 
        for (int 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) { 
        if (b == 0) 
            return a; 
        return gcd(b, a % b);  
    } 
    static long fast_pow(long base,long n,long M){
        if(n==0)
           return 1;
        if(n==1)
        return base;
        long halfn=fast_pow(base,n/2,M);
        if(n%2==0)
            return ( halfn * halfn ) % M;
        else
            return ( ( ( halfn * halfn ) % M ) * base ) % M;
    }
    static long modInverse(long n,long M){
        return fast_pow(n,M-2,M);
    }
 
    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;
 
        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }
 
        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }
        public int nextInt() {
            return Integer.parseInt(next());
        }
        public long nextLong() {
            return Long.parseLong(next());
        }
    }
}

Measured memory_bytes: 49780