#include <bits/stdc++.h>
#define pb push_back
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n;
cin >> n;
vector<pair<int, int>> building; // building[id] = (xi, yi)
vector<pair<int, int>> building_mapper; // building_mapper => sort
for (int i = 0; i < n; i ++) {
int x, y;
cin >> x >> y;
building.pb({x, y});
building_mapper.pb({y, i});
}
vector<bool> is_covered(n+1, false);
sort(building_mapper.begin(), building_mapper.end(), [](pair<int, int> a, pair<int, int> b){
return a.first > b.first;
});
int ans = 0;
for (int i = 0; i < n; i ++) {
if (is_covered[building_mapper[i].second]) {continue;}
ans ++;
pair<int, int> cur_building = building[building_mapper[i].second];
is_covered[building_mapper[i].second] = true;
for (int j = building_mapper[i].second-1; j >= 0; j --) { // check the left side of cur_building
if ( abs(building[j].first - cur_building.first) <= abs(building[j].second - cur_building.second) ) {
is_covered[j] = true;
} else {
break;
}
}
for (int j = building_mapper[i].second+1; j < n; j ++) { // check the right side of cur_building
if ( abs(building[j].first - cur_building.first) <= abs(building[j].second - cur_building.second) ) {
is_covered[j] = true;
} else {
break;
}
}
}
cout << ans << endl;
}
// key idea:
// 1. find the tallest building that is not covered yet
// 2. plant a lightning rod there
// 3. check the left and right side of the building
// => if the building is under cover, mark it under cover and continue check
// => if meet a building is not under cover, stop (think why !)
