#include
#include
#define l long long int
using namespace std;
class circle{
public:
int center;
int radius;
int startpoint;
int endpoint;
};
bool compare(circle a,circle b){
if(a.endpoint == b.endpoint){
return a.startpoint < b.startpoint;
}
else{
return a.startpoint < b.startpoint;
}
}
int main(){
int n;
cin>>n;
int center,radius;
circle arr[n];
for(int i=0;i<n;i++){
cin>>center>>radius;
circle x;
x.center = center;
x.radius = radius;
x.startpoint = center-radius;
x.endpoint = center + radius;
arr[i] = x;
}
sort(arr,arr+n,compare);
int count =1;
circle prev= arr[0];
for(int i=1;i<n;i++){
if(arr[i].startpoint >= prev.endpoint){
prev = arr[i];
count++;
}
}
cout<<count;
return 0;
}
