double f(double lambda1, double lambda2, double phi1, double phi2) {
double r20077442 = lambda1;
double r20077443 = lambda2;
double r20077444 = r20077442 - r20077443;
double r20077445 = sin(r20077444);
double r20077446 = phi2;
double r20077447 = cos(r20077446);
double r20077448 = r20077445 * r20077447;
double r20077449 = phi1;
double r20077450 = cos(r20077449);
double r20077451 = sin(r20077446);
double r20077452 = r20077450 * r20077451;
double r20077453 = sin(r20077449);
double r20077454 = r20077453 * r20077447;
double r20077455 = cos(r20077444);
double r20077456 = r20077454 * r20077455;
double r20077457 = r20077452 - r20077456;
double r20077458 = atan2(r20077448, r20077457);
return r20077458;
}