procedure hanoi (n : integer; source,destination,help : char);
begin
   if n=1 then
      writeln('Move a disk from ',source, ' to ',destination)
   else
   begin
      hanoi(n-1,source,help,destination);
      hanoi(1,source,destination,help);
      hanoi(n-1,help,destination,source);
   end;
end;