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 r437985 = x;
        double r437986 = 1.0;
        double r437987 = r437985 + r437986;
        double r437988 = sqrt(r437987);
        double r437989 = sqrt(r437985);
        double r437990 = r437988 - r437989;
        double r437991 = y;
        double r437992 = r437991 + r437986;
        double r437993 = sqrt(r437992);
        double r437994 = sqrt(r437991);
        double r437995 = r437993 - r437994;
        double r437996 = r437990 + r437995;
        double r437997 = z;
        double r437998 = r437997 + r437986;
        double r437999 = sqrt(r437998);
        double r438000 = sqrt(r437997);
        double r438001 = r437999 - r438000;
        double r438002 = r437996 + r438001;
        double r438003 = t;
        double r438004 = r438003 + r437986;
        double r438005 = sqrt(r438004);
        double r438006 = sqrt(r438003);
        double r438007 = r438005 - r438006;
        double r438008 = r438002 + r438007;
        return r438008;
}