#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
using vpii = vector<pii>;
bool forces (pii parent, pii child) {
int dx = abs(parent.first - child.first);
int dE = parent.second - child.second;
return dx <= dE;
}
int main () {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int N;
cin >> N;
vpii people_array;
for (int i = 0; i < N; i ++) {
int x, E;
cin >> x >> E;
people_array.push_back({ x, E });
}
sort(people_array.begin(), people_array.end());
vpii stack;
for (pii man : people_array) {
if (stack.size() != 0 && forces(stack.back(), man)) continue ;
while (stack.size() != 0 && forces(man, stack.back())) stack.pop_back();
stack.push_back(man);
}
cout << stack.size() << "\n";
}
