#pragma GCC optimize("Ofast") #pragma GCC optimize("O3,unroll-loops") #include <bits/stdc++.h> using namespace std; #define f0r(i, n) for (auto i = 0; i < (n); ++i) #define fnr(i, n, k) for (auto i = (n); i < (k); ++i) #define all(v) (v).begin(), (v).end() #define pb push_back #define F first #define S second #define ctn(x) cout << x << '\n' #define forl(a, l) for (auto a : l) #define ctl(l) for (auto &a : (l)) cout << a << ' '; cout << '\n'; #define lb(v, x) (lower_bound(all(v), x) - begin(v)) #define ub(v, x) (upper_bound(all(v), x) - begin(v)) #define pq priority_queue template <class T> using V = vector<T>; using ll = long long; using vi = V<int>; using vl = V<ll>; using pi = pair<int, int>; using ti = tuple<int, int, int>; using Adj = V<vi>; using vvi = V<vi>; struct ST { vi tr; int N; ST(int n) { for (N=1; N<n; N*=2); tr.assign(2*N, 2e9); } #define m (l+r)/2 int query(int ql, int qr, int v, int l, int r) { if (qr < l || r < ql) return 2e9; if (ql <= l && r <= qr) return tr[v]; return min(query(ql, qr, 2*v, l, m), query(ql, qr, 2*v+1, m+1, r)); } void upd(int q, int x, int v, int l, int r) { if (q < l || r < q) return; if (l == r) { tr[v] = min(tr[v], x); return; } upd(q, x, 2*v, l, m); upd(q, x, 2*v+1, m+1, r); tr[v] = min(tr[2*v], tr[2*v+1]); } #undef m int query(int ql, int qr) { return query(ql, qr, 1, 0, N-1); } void upd(int q, int x) { upd(q, x, 1, 0, N-1); } }; int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); int N; cin >> N; V<pi> ppl(N); vi xs; for (auto &[e, x]: ppl) { cin >> x >> e; xs.pb(x); } sort(all(xs)); xs.erase(unique(all(xs)), end(xs)); sort(all(ppl), greater<>()); ST st1(xs.size()), st2(xs.size()); int cnt = 0; for (auto &[e, x]: ppl) { int i = lower_bound(all(xs), x) - begin(xs); if (st1.query(i, xs.size()-1) <= x - e || st2.query(0, i) <= -(e + x)) continue; ++cnt; st1.upd(i, x - e); st2.upd(i, -e -x); } ctn(cnt); }