#include <bits/stdc++.h>
using namespace std;
using ll = int;
#define vi vector<long long>
#define all(x) x.begin(), x.end()
#define endl "\n"
#define pr pair<ll, ll>
#define ff first
#define ss second
void solution();
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
solution();
return 0;
}
const int N = 1e7+10;
pr a[N];
void solution() {
ll n; cin >> n;
for (int i = 0; i < n; i++) {
cin >> a[i].ff >> a[i].ss;
}
vi avl;
auto isValid = [&](int i, int j) {
// jth index has light rod
return abs(a[i].ff-a[j].ff) <= a[j].ss-a[i].ss;
};
for (int i = 0; i < n; i++) {
if (avl.size() == 0) avl.push_back(i);
else {
if (isValid(i, avl.back())) continue;
else {
while (avl.size() > 0 && isValid(avl.back(), i)) avl.pop_back();
avl.push_back(i);
}
}
}
cout << avl.size() << endl;
}
