#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>
using namespace std;
typedef long long ll;
struct Building {
ll A; // X - Y
ll B; // X + Y
};
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<Building> buildings(n);
for (int i = 0; i < n; i++){
ll X, Y;
cin >> X >> Y;
buildings[i].A = X - Y;
buildings[i].B = X + Y;
}
// Sort by B descending. For equal B, sort by A ascending.
sort(buildings.begin(), buildings.end(), [](const Building &a, const Building &b) {
if(a.B == b.B) return a.A < b.A;
return a.B > b.B;
});
ll bestA = LLONG_MAX; // best (smallest) A among chosen rods
int ans = 0;
for(auto &b : buildings){
// A building is covered by some rod if some chosen rod's A <= its A.
if(bestA <= b.A)
continue;
// Otherwise, plant a rod here and update bestA.
ans++;
bestA = b.A;
}
cout << ans << "\n";
return 0;
}
