import std.stdio;
import std.conv;
import std.string;
import std.typecons;
import std.algorithm;
import std.array;
import std.range;
import std.math;
import std.regex : regex;
import std.container;
import std.bigint;


void main()
{
  auto n = readln.chomp.to!int;
  auto xl = new long[][](n, 2);
  foreach (i; 0..n) {
    xl[i] = readln.chomp.split.to!(long[]);
  }
  sort(xl);
  auto res = n;
  auto max = xl[0][0] + xl[0][1] - 1;
  
  foreach (i; 1..n) {
    if (max >= xl[i][0] - xl[i][1]) {
      res--;
    } else {
      max = xl[i][0] + xl[i][1] - 1;
    }
  }
  res.writeln;
}
