/**
* code generated by JHelper
* More info: https://github.com/AlexeyDmitriev/JHelper
* @author win11905
*/
#include <bits/stdc++.h>
#define all(x) (x).begin(), (x).end()
#define vi vector<int>
#define iii tuple<int, int, int>
#define long long long
#define pii pair<int, int>
#define x first
#define y second
using namespace std;
const long MOD = 1e9+7, LINF = 1e18 + 1e16;
const int INF = 1e9+1;
const double EPS = 1e-10;
const int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};
class lightningrod {
private:
int n;
stack<pii> stk;
bool check_cover(pii a, pii b) {
return abs(a.x - b.x) <= a.y - b.y;
}
public:
void solve(istream& cin, ostream& cout) {
cin >> n;
vector<pii> vec;
for(int i = 0, a, b; i < n; ++i) {
cin >> a >> b;
vec.emplace_back(a, b);
}
sort(vec.begin(), vec.end(), [&](const pii &a, const pii &b) {
if(a.x == b.x) return a.y > b.y;
return a.x < b.x;
});
for(auto v : vec) {
if(stk.empty()) {
stk.emplace(v);
continue;
}
if(check_cover(stk.top(), v)) continue;
while(!stk.empty() && check_cover(v, stk.top())) stk.pop();
stk.emplace(v);
}
cout << stk.size() << endl;
}
};
class Solver {
public:
void solve(std::istream& in, std::ostream& out) {
lightningrod *obj = new lightningrod();
obj->solve(in, out);
}
};
int32_t main() {
ios::sync_with_stdio(false);
cin.tie(0);
Solver solver;
std::istream& in(std::cin);
std::ostream& out(std::cout);
solver.solve(in, out);
return 0;
}
