"use strict"
 
function Main(s) {
  s = s.split('\n');
  let n = Number(s[0]);
  // const robos = s.slice(1, s.length);
 
  const l = s.slice(1, s.length).map(robo => {
    let t = robo.split(' ').map(Number);
    return [t[0]-t[1], t[0]+t[1]];
  })
  l.sort((a, b) => a[1] < b[1]);

  let range = [-1e10];
  for(let i=0; i <l.length; ++i){
    const min = l[i][0];
    const max = l[i][1];

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