#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define ff first
#define ss second
#define pb push_back
bool contain(pii lhs, pii rhs) {
return abs(lhs.ff - rhs.ff) <= (lhs.ss - rhs.ss);
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
int n; cin >> n;
pii a[n];
for (int i = 0; i < n; i++) cin >> a[i].ff >> a[i].ss;
sort(a, a + n);
vector<pii> sel;
for (int i = 0; i < n; i++) {
while (!sel.empty()) {
if (contain(a[i], sel.back())) sel.pop_back();
else break;
}
if (sel.empty() || !contain(sel.back(), a[i])) {
sel.pb(a[i]);
}
}
cout << sel.size() << '\n';
}
