double f(double lambda1, double lambda2, double phi1, double phi2) {
double r8488092 = lambda1;
double r8488093 = lambda2;
double r8488094 = r8488092 - r8488093;
double r8488095 = sin(r8488094);
double r8488096 = phi2;
double r8488097 = cos(r8488096);
double r8488098 = r8488095 * r8488097;
double r8488099 = phi1;
double r8488100 = cos(r8488099);
double r8488101 = sin(r8488096);
double r8488102 = r8488100 * r8488101;
double r8488103 = sin(r8488099);
double r8488104 = r8488103 * r8488097;
double r8488105 = cos(r8488094);
double r8488106 = r8488104 * r8488105;
double r8488107 = r8488102 - r8488106;
double r8488108 = atan2(r8488098, r8488107);
return r8488108;
}