double f(double lambda1, double lambda2, double phi1, double phi2) {
double r3535406 = lambda1;
double r3535407 = lambda2;
double r3535408 = r3535406 - r3535407;
double r3535409 = sin(r3535408);
double r3535410 = phi2;
double r3535411 = cos(r3535410);
double r3535412 = r3535409 * r3535411;
double r3535413 = phi1;
double r3535414 = cos(r3535413);
double r3535415 = sin(r3535410);
double r3535416 = r3535414 * r3535415;
double r3535417 = sin(r3535413);
double r3535418 = r3535417 * r3535411;
double r3535419 = cos(r3535408);
double r3535420 = r3535418 * r3535419;
double r3535421 = r3535416 - r3535420;
double r3535422 = atan2(r3535412, r3535421);
return r3535422;
}