Usage: ztravel [-n|-s|-t|-c|-u] <seed> <#cities> <#planes> <#people> [distance]

It is a domain which transport people between cities with airplanes while refueling them to keep them flying.

If distance is a positive value then the distances between
locations is set randomly using this value as the bound.
However, this feature does not affect the output in STRIPS mode.

Distance also sets the initial fuel level of the planes.

IPC instances:

           planes person cities
p01.pddl:   1    2       3 
p02.pddl:   1    3       3 
p03.pddl:   2    4       3 
p04.pddl:   2    5       3 
p05.pddl:   2    4       4 
p06.pddl:   2    5       4 
p07.pddl:   2    6       4 
p08.pddl:   3    6       5 
p09.pddl:   3    7       5 
p10.pddl:   3    8       5 
p11.pddl:   3    7       6 
p12.pddl:   3    8       6 
p13.pddl:   3    10      6 
p14.pddl:   5    10      10
p15.pddl:   5    15      12
p16.pddl:   5    15      14
p17.pddl:   5    20      16
p18.pddl:   5    20      18
p19.pddl:   5    25      20
p20.pddl:   5    25      22

