double f(double lambda1, double lambda2, double phi1, double phi2) {
double r2455380 = lambda1;
double r2455381 = lambda2;
double r2455382 = r2455380 - r2455381;
double r2455383 = sin(r2455382);
double r2455384 = phi2;
double r2455385 = cos(r2455384);
double r2455386 = r2455383 * r2455385;
double r2455387 = phi1;
double r2455388 = cos(r2455387);
double r2455389 = sin(r2455384);
double r2455390 = r2455388 * r2455389;
double r2455391 = sin(r2455387);
double r2455392 = r2455391 * r2455385;
double r2455393 = cos(r2455382);
double r2455394 = r2455392 * r2455393;
double r2455395 = r2455390 - r2455394;
double r2455396 = atan2(r2455386, r2455395);
return r2455396;
}