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 r459221 = x;
        double r459222 = 1.0;
        double r459223 = r459221 + r459222;
        double r459224 = sqrt(r459223);
        double r459225 = sqrt(r459221);
        double r459226 = r459224 - r459225;
        double r459227 = y;
        double r459228 = r459227 + r459222;
        double r459229 = sqrt(r459228);
        double r459230 = sqrt(r459227);
        double r459231 = r459229 - r459230;
        double r459232 = r459226 + r459231;
        double r459233 = z;
        double r459234 = r459233 + r459222;
        double r459235 = sqrt(r459234);
        double r459236 = sqrt(r459233);
        double r459237 = r459235 - r459236;
        double r459238 = r459232 + r459237;
        double r459239 = t;
        double r459240 = r459239 + r459222;
        double r459241 = sqrt(r459240);
        double r459242 = sqrt(r459239);
        double r459243 = r459241 - r459242;
        double r459244 = r459238 + r459243;
        return r459244;
}