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 r22772002 = x;
        double r22772003 = 1.0;
        double r22772004 = r22772002 + r22772003;
        double r22772005 = sqrt(r22772004);
        double r22772006 = sqrt(r22772002);
        double r22772007 = r22772005 - r22772006;
        double r22772008 = y;
        double r22772009 = r22772008 + r22772003;
        double r22772010 = sqrt(r22772009);
        double r22772011 = sqrt(r22772008);
        double r22772012 = r22772010 - r22772011;
        double r22772013 = r22772007 + r22772012;
        double r22772014 = z;
        double r22772015 = r22772014 + r22772003;
        double r22772016 = sqrt(r22772015);
        double r22772017 = sqrt(r22772014);
        double r22772018 = r22772016 - r22772017;
        double r22772019 = r22772013 + r22772018;
        double r22772020 = t;
        double r22772021 = r22772020 + r22772003;
        double r22772022 = sqrt(r22772021);
        double r22772023 = sqrt(r22772020);
        double r22772024 = r22772022 - r22772023;
        double r22772025 = r22772019 + r22772024;
        return r22772025;
}