Main(myin());
function myin(){return require("fs").readFileSync("/dev/stdin", "utf8").trim();}
function myout(t){console.log(t);}//standard output
function myerr(t){console.error(t);}//standard error
//[no]param
//不明値:何もしない  1:数値へ変換  2:半角SPで分割  3:改行で分割  4:半角SPで分割し、数値配列へ
//5:改行で分割し、数値配列へ  6:1文字に分割  7:1文字に分割し、数値配列へ
//8:半角SPで結合　9:改行で結合　0:文字なしで結合
function myconv(i,no){switch(no){case 1:return parseInt(i);case 2:return i.split(" ");case 3:return i.split("\n");case 4:return i.split(" ").map((a)=>Number(a));case 5:return i.split("\n").map((a)=>Number(a));case 6:return i.split("");case 7:return i.split("").map((a)=>Number(a));case 8:return i.join(" ");case 9:return i.join("\n");case 0:return i.join("");default:return i;}}
function Main(input) {
  input = myconv(input,3);
  var N = myconv(input[0],1);
  var used = {
    "min" : 0,
    "max" : 0,
  }
  input.shift();
  var output = N;
  var list = new Array(N);
  for(var i = 0; i < N;i++){
    var tmp = myconv(input[i],4);
    list[i] = {
      "pos" : tmp[0],
      "len" : tmp[1]
    };
  }
  list.sort(function(a,b){
    return a["pos"]-b["pos"];
  });
  for(var i = 0; i < N; i++){
    var tmp = list[i];
    myerr(tmp);
    if(i == 0){
       used["min"] = Math.max(tmp["pos"]-tmp["len"],0);
      used["max"] = tmp["pos"]+tmp["len"];
    }else{
      if(used["max"] <= tmp["pos"]-tmp["len"]){
         used["max"] = tmp["pos"]+tmp["len"];
      }else{
       output--; 
      }
    }
  }
  myout(output);
  
}