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 r408674 = x;
        double r408675 = 1.0;
        double r408676 = r408674 + r408675;
        double r408677 = sqrt(r408676);
        double r408678 = sqrt(r408674);
        double r408679 = r408677 - r408678;
        double r408680 = y;
        double r408681 = r408680 + r408675;
        double r408682 = sqrt(r408681);
        double r408683 = sqrt(r408680);
        double r408684 = r408682 - r408683;
        double r408685 = r408679 + r408684;
        double r408686 = z;
        double r408687 = r408686 + r408675;
        double r408688 = sqrt(r408687);
        double r408689 = sqrt(r408686);
        double r408690 = r408688 - r408689;
        double r408691 = r408685 + r408690;
        double r408692 = t;
        double r408693 = r408692 + r408675;
        double r408694 = sqrt(r408693);
        double r408695 = sqrt(r408692);
        double r408696 = r408694 - r408695;
        double r408697 = r408691 + r408696;
        return r408697;
}