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 r411445 = x;
        double r411446 = 1.0;
        double r411447 = r411445 + r411446;
        double r411448 = sqrt(r411447);
        double r411449 = sqrt(r411445);
        double r411450 = r411448 - r411449;
        double r411451 = y;
        double r411452 = r411451 + r411446;
        double r411453 = sqrt(r411452);
        double r411454 = sqrt(r411451);
        double r411455 = r411453 - r411454;
        double r411456 = r411450 + r411455;
        double r411457 = z;
        double r411458 = r411457 + r411446;
        double r411459 = sqrt(r411458);
        double r411460 = sqrt(r411457);
        double r411461 = r411459 - r411460;
        double r411462 = r411456 + r411461;
        double r411463 = t;
        double r411464 = r411463 + r411446;
        double r411465 = sqrt(r411464);
        double r411466 = sqrt(r411463);
        double r411467 = r411465 - r411466;
        double r411468 = r411462 + r411467;
        return r411468;
}