#include #include #include #include #include #include #include #include #include using namespace std; #define loop(i,a,b) for(int i=(a);i struct tuple_printer { static void print(std::ostream& out, const Type& value) { out << std::get(value) << ", "; tuple_printer::print(out, value); } }; template struct tuple_printer < Type, N, N > { static void print(std::ostream& out, const Type& value) { out << std::get(value); } }; template std::ostream& operator<<(std::ostream& out, const std::tuple& value) { out << "("; tuple_printer, 0, sizeof...(Types)-1>::print(out, value); out << ")"; return out; } #ifdef DEBUG #define dump(...) (cerr << #__VA_ARGS__ << " = " << make_tuple(__VA_ARGS__) << " [" << __LINE__ << "]" << endl) #else #define dump(...) #endif int main(){ set> exi; int n; cin >> n; int ans = 0; rep(i, n){ int x, y; cin >> x >> y; bool hit = false; for (int iy = y - 10; !hit && iy <= y + 10; iy++){ for (int ix = x - 10; !hit && ix <= x + 10; ix++){ if (exi.count(make_pair(ix, iy))==0) continue; int dx = ix - x; int dy = iy - y; int d2 = dx*dx + dy*dy; if (d2 < 400) hit = true; } } if (!hit) { ans++; exi.emplace(x, y); } } cout << ans << endl; }