//#define _GLIBCXX_DEBUG #include <bits/stdc++.h> #define int long long using namespace std; const int INF = 1e17; struct node { int maxx_val = -INF; node *left ; node *right; node() { maxx_val = -INF; left = 0; right = 0; } node * go_to_l() { if (!left) left = new node(); return left; } node * go_to_r() { if (!right) right = new node(); return right; } }; void upd(node *u,int l,int r,int val,int pos) { if (r - l == 1) { u->maxx_val = max(val,u->maxx_val); return; } int mid = (l + r) / 2; if (pos < mid) { upd(u->go_to_l(),l,mid,val,pos); }else { upd(u->go_to_r(),mid,r,val,pos); } u->maxx_val = max(u->go_to_l()->maxx_val,u->go_to_r()->maxx_val); } int get(node *u,int l,int r,int ql,int qr) { if (r <= ql || l >= qr) return -INF; if (l >= ql && r <= qr) return u->maxx_val; int mid = (l + r) / 2; return max(get(u->go_to_l(),l,mid,ql,qr),get(u->go_to_r(),mid,r,ql,qr)); } signed main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int n; cin >> n; vector <pair<int,int>> vec(n); for (int i = 0;i < n;i++) { cin >> vec[i].second >> vec[i].first; } sort(vec.begin(), vec.end()); int ans = 0; node* root1 = new node(); node* root2 = new node(); int L = 0; int R = 1e10; for (int i = n - 1;i >= 0;i--) { int v1 = vec[i].first + vec[i].second; int v2 = vec[i].first - vec[i].second; int var1 = get(root1,L,R,0,vec[i].second); int var2 = get(root2,L,R,vec[i].second,R); if (v1 > var1 && v2 > var2) { ans++; } upd(root1,L,R,v1,vec[i].second); upd(root2,L,R,v2,vec[i].second); } cout << ans << '\n'; }