import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.*;
public class Main {
public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
int n = Integer.parseInt(br.readLine());
List<Resident> residents = new ArrayList<>();
for(int i = 0; i < n; i++){
StringTokenizer st = new StringTokenizer(br.readLine());
int x = Integer.parseInt(st.nextToken());
int e = Integer.parseInt(st.nextToken());
Resident r = new Resident(e-x, e+x);
residents.add(r);
}
br.close();
Collections.sort(residents);
Stack<Resident> stack = new Stack<>();
for(Resident r : residents) {
while(!stack.isEmpty() && stack.peek().add <= r.add){
stack.pop();
}
stack.push(r);
}
System.out.println(stack.size());
}
static class Resident implements Comparable<Resident> {
int sub;
int add;
public Resident (int sub, int add){
this.sub = sub;
this.add = add;
}
public int compareTo (Resident r){
if(this.sub == r.sub){
return this.add-r.add;
}
return this.sub-r.sub;
}
}
}
