All-different constraint: solving an assignment problem

(!****************************************************************
   CP example problems
   ===================
   
   file alldiff.mos
   ````````````````
   all_different constraints.

   (c) 2008 Artelys S.A. and Fair Isaac Corporation
       Creation: 2005
*****************************************************************!)
model "all_different example"
 uses "kalis"

 declarations  
  PEOPLE = {"Sebastian", "Frederic", "Jan-Georg",
            "Krzysztof","Maarten","Luca"}  ! Set of speakers  
  x: array(PEOPLE) of cpvar                ! Time slot per person    
 end-declarations

 3 <= x("Sebastian") ; x("Sebastian") <= 6
 3 <= x("Frederic")  ;  x("Frederic") <= 4
 2 <= x("Jan-Georg") ; x("Jan-Georg") <= 5
 2 <= x("Krzysztof") ; x("Krzysztof") <= 4
 3 <= x("Maarten")   ;   x("Maarten") <= 4
 1 <= x("Luca")      ;      x("Luca") <= 6

! A different time slot for every person
 all_different(x)

! Solve the problem
 if not cp_find_next_sol then
  writeln("Problem is infeasible")
  exit(1)
 end-if 

! Solution printout 
 writeln(x)

end-model