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 r33309 = x;
        double r33310 = 1.0;
        double r33311 = r33309 + r33310;
        double r33312 = sqrt(r33311);
        double r33313 = sqrt(r33309);
        double r33314 = r33312 - r33313;
        double r33315 = y;
        double r33316 = r33315 + r33310;
        double r33317 = sqrt(r33316);
        double r33318 = sqrt(r33315);
        double r33319 = r33317 - r33318;
        double r33320 = r33314 + r33319;
        double r33321 = z;
        double r33322 = r33321 + r33310;
        double r33323 = sqrt(r33322);
        double r33324 = sqrt(r33321);
        double r33325 = r33323 - r33324;
        double r33326 = r33320 + r33325;
        double r33327 = t;
        double r33328 = r33327 + r33310;
        double r33329 = sqrt(r33328);
        double r33330 = sqrt(r33327);
        double r33331 = r33329 - r33330;
        double r33332 = r33326 + r33331;
        return r33332;
}