double f(double lambda1, double lambda2, double phi1, double phi2) {
double r30214771 = lambda1;
double r30214772 = lambda2;
double r30214773 = r30214771 - r30214772;
double r30214774 = sin(r30214773);
double r30214775 = phi2;
double r30214776 = cos(r30214775);
double r30214777 = r30214774 * r30214776;
double r30214778 = phi1;
double r30214779 = cos(r30214778);
double r30214780 = sin(r30214775);
double r30214781 = r30214779 * r30214780;
double r30214782 = sin(r30214778);
double r30214783 = r30214782 * r30214776;
double r30214784 = cos(r30214773);
double r30214785 = r30214783 * r30214784;
double r30214786 = r30214781 - r30214785;
double r30214787 = atan2(r30214777, r30214786);
return r30214787;
}