"use strict"
 
function Main(s) {
  s = s.split('\n');
  let n = Number(s[0]);
  const robos = s.slice(1, s.length);
 
  robos.sort((a, b)=> Number(a.split(' ')[0])+Number(a.split(' ')[1]) > Number(b.split(' ')[0])+Number(b.split(' ')[1]));
 
  let range = [-1e9];
  for(let i=0; i <robos.length; ++i){
    const x = Number(robos[i].split(' ')[0]);
    const l = Number(robos[i].split(' ')[1]);
    const min = x-l;
    const max = x+l;
 
    if(Math.max(null, range) > min) {
      n=n-1;
    } else {
      range.push(max);
    }
  }
 
  console.log(n);
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));
