double f(double lambda1, double lambda2, double phi1, double phi2) {
double r1115537 = lambda1;
double r1115538 = phi2;
double r1115539 = cos(r1115538);
double r1115540 = lambda2;
double r1115541 = r1115537 - r1115540;
double r1115542 = sin(r1115541);
double r1115543 = r1115539 * r1115542;
double r1115544 = phi1;
double r1115545 = cos(r1115544);
double r1115546 = cos(r1115541);
double r1115547 = r1115539 * r1115546;
double r1115548 = r1115545 + r1115547;
double r1115549 = atan2(r1115543, r1115548);
double r1115550 = r1115537 + r1115549;
return r1115550;
}