Cannot sample enough valid points. (more)

\[\left(\left(\left(\sqrt{x + 1} - \sqrt{x}\right) + \left(\sqrt{y + 1} - \sqrt{y}\right)\right) + \left(\sqrt{z + 1} - \sqrt{z}\right)\right) + \left(\sqrt{t + 1} - \sqrt{t}\right)\]
\left(\left(\left(\sqrt{x + 1} - \sqrt{x}\right) + \left(\sqrt{y + 1} - \sqrt{y}\right)\right) + \left(\sqrt{z + 1} - \sqrt{z}\right)\right) + \left(\sqrt{t + 1} - \sqrt{t}\right)
double f(double x, double y, double z, double t) {
        double r473633 = x;
        double r473634 = 1.0;
        double r473635 = r473633 + r473634;
        double r473636 = sqrt(r473635);
        double r473637 = sqrt(r473633);
        double r473638 = r473636 - r473637;
        double r473639 = y;
        double r473640 = r473639 + r473634;
        double r473641 = sqrt(r473640);
        double r473642 = sqrt(r473639);
        double r473643 = r473641 - r473642;
        double r473644 = r473638 + r473643;
        double r473645 = z;
        double r473646 = r473645 + r473634;
        double r473647 = sqrt(r473646);
        double r473648 = sqrt(r473645);
        double r473649 = r473647 - r473648;
        double r473650 = r473644 + r473649;
        double r473651 = t;
        double r473652 = r473651 + r473634;
        double r473653 = sqrt(r473652);
        double r473654 = sqrt(r473651);
        double r473655 = r473653 - r473654;
        double r473656 = r473650 + r473655;
        return r473656;
}