int main(){
    // 其他
    for (int i = 1; i <= n; i++) {
        int x1, x2, y1, y2;
        cin >> x1 >> y1 >> x2 >> y2;
        ls[i] = SgLine(x1, x2, y1, 1), ls[i + n] = SgLine(x1, x2, y2, -1);
        X[i] = x1, X[i + n] = x2;
    }
    n <<= 1;
    int cnt = unique(X + 1, X + 1 + n) - (X + 1);
    sort(X + 1, X + 1 + n);
    sort(ls + 1, ls + 1 + n);
    build(1, 1, cnt - 1);
    // 其他
}