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 r348968 = x;
        double r348969 = 1.0;
        double r348970 = r348968 + r348969;
        double r348971 = sqrt(r348970);
        double r348972 = sqrt(r348968);
        double r348973 = r348971 - r348972;
        double r348974 = y;
        double r348975 = r348974 + r348969;
        double r348976 = sqrt(r348975);
        double r348977 = sqrt(r348974);
        double r348978 = r348976 - r348977;
        double r348979 = r348973 + r348978;
        double r348980 = z;
        double r348981 = r348980 + r348969;
        double r348982 = sqrt(r348981);
        double r348983 = sqrt(r348980);
        double r348984 = r348982 - r348983;
        double r348985 = r348979 + r348984;
        double r348986 = t;
        double r348987 = r348986 + r348969;
        double r348988 = sqrt(r348987);
        double r348989 = sqrt(r348986);
        double r348990 = r348988 - r348989;
        double r348991 = r348985 + r348990;
        return r348991;
}