/* Author: Nguyen Chi Thanh - High School for the Gifted - VNU.HCM (i2528) */ #include <bits/stdc++.h> using namespace std; // #define int long long #define ull unsigned long long #define ld long double #define pii pair<int, int> #define fi first #define se second #define __builtin_popcount __builtin_popcountll #define all(x) (x).begin(), (x).end() #define BIT(x, i) (((x) >> (i)) & 1) #define MASK(x) ((1ll << (x))) #define debug(a, l, r) for (int _i = (l); _i <= (r); ++_i) cout << (a)[_i] << ' '; cout << '\n'; int n; void solve() { cin >> n; vector<pii> st; for (int i = 1; i <= n; ++i) { int x, y; cin >> x >> y; pii p = {x + y, x - y}; bool need = 1; while (!st.empty()) { int _x = st.back().fi, _y = st.back().se; if (p.fi <= _x && p.se >= _y) { need = 0; break; } if (_x <= p.fi && _y >= p.se) st.pop_back(); else break; } if (need) st.push_back(p); } cout << (int)st.size(); } signed main() { #ifdef NCTHANH freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout); #endif ios_base::sync_with_stdio(0); cin.tie(nullptr); cout.tie(nullptr); solve(); return 0; }