type town = (a,b,c,d,e,f,g,h);
towns = set of town;
path = array [town] towns of;
Describe the procedure travel(P,H,K), which is the flight P (P[x] is the set of cities that can in one trip by bus from x) defines a K – variety of cities in which you can get a bus (during one trip or through other cities) from H.