Hello, everyone.

Just wanted to summarize some info about this problem.

Ok, my code got AC with following things in it:

1. My pi was 3.1415926535897932384626433 (perhaps it is enough)

2. I used this formula from wikipedia

deltaArc=acos(sin(phiA)*sin(phiB)+cos(phiA)*cos(phiB)*cos(deltaL));

distance = deltaArc*3437.5;

(see the first formula from wikipedia

http://en.wikipedia.org/wiki/Great-circle_distance)3. I used the following condition:

if(100.00-distance>0.005) printf("DANGER!\n");

Hope it will help somebody.