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 r404246 = x;
        double r404247 = 1.0;
        double r404248 = r404246 + r404247;
        double r404249 = sqrt(r404248);
        double r404250 = sqrt(r404246);
        double r404251 = r404249 - r404250;
        double r404252 = y;
        double r404253 = r404252 + r404247;
        double r404254 = sqrt(r404253);
        double r404255 = sqrt(r404252);
        double r404256 = r404254 - r404255;
        double r404257 = r404251 + r404256;
        double r404258 = z;
        double r404259 = r404258 + r404247;
        double r404260 = sqrt(r404259);
        double r404261 = sqrt(r404258);
        double r404262 = r404260 - r404261;
        double r404263 = r404257 + r404262;
        double r404264 = t;
        double r404265 = r404264 + r404247;
        double r404266 = sqrt(r404265);
        double r404267 = sqrt(r404264);
        double r404268 = r404266 - r404267;
        double r404269 = r404263 + r404268;
        return r404269;
}