double f(double lambda1, double lambda2, double phi1, double phi2) {
double r3630177 = lambda1;
double r3630178 = lambda2;
double r3630179 = r3630177 - r3630178;
double r3630180 = sin(r3630179);
double r3630181 = phi2;
double r3630182 = cos(r3630181);
double r3630183 = r3630180 * r3630182;
double r3630184 = phi1;
double r3630185 = cos(r3630184);
double r3630186 = sin(r3630181);
double r3630187 = r3630185 * r3630186;
double r3630188 = sin(r3630184);
double r3630189 = r3630188 * r3630182;
double r3630190 = cos(r3630179);
double r3630191 = r3630189 * r3630190;
double r3630192 = r3630187 - r3630191;
double r3630193 = atan2(r3630183, r3630192);
return r3630193;
}