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 r565211 = x;
        double r565212 = 1.0;
        double r565213 = r565211 + r565212;
        double r565214 = sqrt(r565213);
        double r565215 = sqrt(r565211);
        double r565216 = r565214 - r565215;
        double r565217 = y;
        double r565218 = r565217 + r565212;
        double r565219 = sqrt(r565218);
        double r565220 = sqrt(r565217);
        double r565221 = r565219 - r565220;
        double r565222 = r565216 + r565221;
        double r565223 = z;
        double r565224 = r565223 + r565212;
        double r565225 = sqrt(r565224);
        double r565226 = sqrt(r565223);
        double r565227 = r565225 - r565226;
        double r565228 = r565222 + r565227;
        double r565229 = t;
        double r565230 = r565229 + r565212;
        double r565231 = sqrt(r565230);
        double r565232 = sqrt(r565229);
        double r565233 = r565231 - r565232;
        double r565234 = r565228 + r565233;
        return r565234;
}