double f(double lambda1, double lambda2, double phi1, double phi2) {
double r3928624 = lambda1;
double r3928625 = lambda2;
double r3928626 = r3928624 - r3928625;
double r3928627 = sin(r3928626);
double r3928628 = phi2;
double r3928629 = cos(r3928628);
double r3928630 = r3928627 * r3928629;
double r3928631 = phi1;
double r3928632 = cos(r3928631);
double r3928633 = sin(r3928628);
double r3928634 = r3928632 * r3928633;
double r3928635 = sin(r3928631);
double r3928636 = r3928635 * r3928629;
double r3928637 = cos(r3928626);
double r3928638 = r3928636 * r3928637;
double r3928639 = r3928634 - r3928638;
double r3928640 = atan2(r3928630, r3928639);
return r3928640;
}