double f(double x, double y, double z, double t, double a) {
double r420252 = x;
double r420253 = y;
double r420254 = r420252 + r420253;
double r420255 = log(r420254);
double r420256 = z;
double r420257 = log(r420256);
double r420258 = r420255 + r420257;
double r420259 = t;
double r420260 = r420258 - r420259;
double r420261 = a;
double r420262 = 0.5;
double r420263 = r420261 - r420262;
double r420264 = log(r420259);
double r420265 = r420263 * r420264;
double r420266 = r420260 + r420265;
return r420266;
}