#include<bits/stdc++.h>
#define int long long
#define pii pair<int, int>
#define X first
#define Y second
#define see(x) cerr << #x << " " << x << "\n";
using namespace std;
struct TREE{
struct node{
node *l, *r;
int val;
node(){
l = r = nullptr;
val = -2e9;
}
}*root;
TREE(){
root = nullptr;
}
int query(int qx, node *n, int l = 1, int r = 1e9){
if(!n) return -2e9;
int mid = l + r >> 1;
if(qx <= mid) return max(n->val, query(qx, n->l, l, mid));
else return max(n->val, query(qx, n->r, mid + 1, r));
}
void modify(int ql, int qr, int qv, node *&n, int l = 1, int r = 1e9){
if(!n) n = new node;
if(ql <= l && r <= qr){
n->val = max(n->val, qv);
return;
}
int mid = l + r >> 1;
if(ql <= mid) modify(ql, qr, qv, n->l, l, mid);
if(qr > mid) modify(ql, qr, qv, n->r, mid + 1, r);
}
};
signed main(){
int n;
cin >> n;
vector< pii > v(n);
TREE l, r;
priority_queue< pii > pq;
for(int i = 0; i < n; ++i){
cin >> v[i].X >> v[i].Y;
pq.push({v[i].Y, i});
}
int ans = 0;
while(!pq.empty()){
int id = pq.top().Y; pq.pop();
if(l.query(v[id].X, l.root) >= v[id].Y - v[id].X){
continue;
}
if(r.query(v[id].X, r.root) >= v[id].Y + v[id].X){
continue;
}
++ans;
l.modify(1, v[id].X, v[id].Y - v[id].X, l.root);
r.modify(v[id].X, 1e9, v[id].Y + v[id].X, r.root);
}
cout << ans << "\n";
}
/*
|Xi - Xj| <= Ei - Ej
if(Xi > Xj) Ei - Xi >= Ej - Xj
if(Xi < Xj) Ei + Xi >= Ej + Xj
*/
