"use strict"
 
function Main(s) {
  s = s.split('\n');
  let n = Number(s[0]);
  const robos = s.slice(1, s.length);
 
  const sort = robos.sort((a, b)=> Number(a.split(' ')[0]) < Number(b.split(' ')[0]) ? -1:1);
 
  const tmp = sort[0].split(' ');
  let range = [];

  for(let i=0; i <robos.length; ++i){
    const x = Number(sort[i].split(' ')[0]);
    const l = Number(sort[i].split(' ')[1]);
    const min = x-l;
    const max = x+l;

    if(max <= Math.min.apply(null, range) || Math.max.apply(null, range) <= min) {
      range.push(min, max);
    } else {
      n=n-1;
    }
  }
  console.log(n);
}
 
Main(require("fs").readFileSync("/dev/stdin", "utf8"));