double f(double lambda1, double lambda2, double phi1, double phi2) {
double r3493066 = lambda1;
double r3493067 = lambda2;
double r3493068 = r3493066 - r3493067;
double r3493069 = sin(r3493068);
double r3493070 = phi2;
double r3493071 = cos(r3493070);
double r3493072 = r3493069 * r3493071;
double r3493073 = phi1;
double r3493074 = cos(r3493073);
double r3493075 = sin(r3493070);
double r3493076 = r3493074 * r3493075;
double r3493077 = sin(r3493073);
double r3493078 = r3493077 * r3493071;
double r3493079 = cos(r3493068);
double r3493080 = r3493078 * r3493079;
double r3493081 = r3493076 - r3493080;
double r3493082 = atan2(r3493072, r3493081);
return r3493082;
}