//#include #include //#include using namespace std; //using namespace atcoder; typedef long long ll; typedef long double ld; typedef unsigned int uint; typedef unsigned long long ull; typedef pair p; const int INF = 1e9; const double eps = 1e-7; const ll LINF = ll(1e18); const int MOD = 1000000007; const int dx[4] = {0, 1, 0, -1}, dy[4] = {-1, 0, 1, 0}; const int Dx[8] = {0, 1, 1, 1, 0, -1, -1, -1}, Dy[8] = {-1, -1, 0, 1, 1, 1, 0, -1}; const long double pi = 4 * atan(1); #define yes cout << "Yes" << endl #define YES cout << "YES" << endl #define no cout << "No" << endl #define NO cout << "NO" << endl #define rep(i, n) for (int i = 0; i < n; i++) #define ALL(v) v.begin(), v.end() #define debug(v) \ cout << #v << ":"; \ for (auto x : v) \ { \ cout << x << ' '; \ } \ cout << endl; template bool chmax(T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; } template bool chmin(T &a, const T &b) { if (b < a) { a = b; return 1; } return 0; } //cout<> n; vector x(n), y(n); vector argv; rep(i, n) { cin >> x[i] >> y[i]; argv.push_back(atan2(y[i], x[i])); argv.push_back(atan2(y[i], x[i]) + 2 * pi); argv.push_back(atan2(y[i], x[i]) + 4 * pi); } //debug(argv); sort(ALL(argv)); ll ans = 0; rep(i, n) { int j = i; while (argv[j] - argv[i] <= pi) j++; //鋭角である範囲 int y = j; for (int k = i + 1; k < j; k++) { if(argv[k]-argv[i]>=pi)continue; while (argv[y] - argv[k] < pi-1e-12&&argv[y]-argv[i]>pi+1e-12) { //cout<