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 r458239 = x;
        double r458240 = 1.0;
        double r458241 = r458239 + r458240;
        double r458242 = sqrt(r458241);
        double r458243 = sqrt(r458239);
        double r458244 = r458242 - r458243;
        double r458245 = y;
        double r458246 = r458245 + r458240;
        double r458247 = sqrt(r458246);
        double r458248 = sqrt(r458245);
        double r458249 = r458247 - r458248;
        double r458250 = r458244 + r458249;
        double r458251 = z;
        double r458252 = r458251 + r458240;
        double r458253 = sqrt(r458252);
        double r458254 = sqrt(r458251);
        double r458255 = r458253 - r458254;
        double r458256 = r458250 + r458255;
        double r458257 = t;
        double r458258 = r458257 + r458240;
        double r458259 = sqrt(r458258);
        double r458260 = sqrt(r458257);
        double r458261 = r458259 - r458260;
        double r458262 = r458256 + r458261;
        return r458262;
}