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 r475721 = x;
        double r475722 = 1.0;
        double r475723 = r475721 + r475722;
        double r475724 = sqrt(r475723);
        double r475725 = sqrt(r475721);
        double r475726 = r475724 - r475725;
        double r475727 = y;
        double r475728 = r475727 + r475722;
        double r475729 = sqrt(r475728);
        double r475730 = sqrt(r475727);
        double r475731 = r475729 - r475730;
        double r475732 = r475726 + r475731;
        double r475733 = z;
        double r475734 = r475733 + r475722;
        double r475735 = sqrt(r475734);
        double r475736 = sqrt(r475733);
        double r475737 = r475735 - r475736;
        double r475738 = r475732 + r475737;
        double r475739 = t;
        double r475740 = r475739 + r475722;
        double r475741 = sqrt(r475740);
        double r475742 = sqrt(r475739);
        double r475743 = r475741 - r475742;
        double r475744 = r475738 + r475743;
        return r475744;
}