#include<bits/stdc++.h>

using namespace std;

int tem, temy;

struct px
{
  int a, b;
}x[2000000];

bool cmp(px x,px y)
{
  return x.b < y.b;
}

int main()
{
  int n,sum=1,mi;
  scanf("%d",&n);
  for(int i=1;i<=n;i++) {
    cin>>tem>>temy;
    x[i].a = tem - temy;
    x[i].b = tem + temy;
  }
  sort(x+1,x+n+1,cmp);
  mi=x[1].b;
  int j=1;
  while(j<=n)
  {
    j++;
    if(x[j].a>=mi) {
      sum++;
      mi=x[j].b;
      }
    }
    cout<<sum;
    return 0;
}