Rules
 Open Contest 2006 consists of 9 problems. The competition will last for 21 days, from 23 March 2006 to 14 April 2006. Solutions to all problems can be corrected, but not more than 256 submissions per problem are allowed. Each solution will be executed for a set of tests. Results obtained by your program will be processed by a special Judge Program which will estimate the correctness/effectiveness of your program. In some tasks you will receive a score for your solution. The score will be proportional to the efficiency of the algorithm you applied. Your score will define your place in the rating table for a given problem. Only the best solution of each participant for a given problem will be considered in rating tables. Current results and the information about all sent solutions will be automatically generated by the Sphere Online Judge system and will be accessible for viewing to all participants of competition.
 All contest problems will be split in two groups: classical and challenge. A classical type problem is considered solved if the solution receives accepted status. In the challenge type problems, the task is considered solved if your solution receives nonzero score.
 Any person registered in the Sphere Online Judge system can take part in contest. The solution of problems under several accounts is strictly forbidden and may result in banning/disqualification!

The solution to a problem can be written in any programming language supported
by Sphere Online Judge, unless it is
otherwise stipulated in a condition of the problem. The number of
submitted solutions to a specific problem for a given participant is limited by
256 from above. Further submissions are not taken into consideration
in the calculation of final statistics. The score for problem X is calculated
from the formula:
 For problems of the classical type: table_score = nominal_task_score + t, parameter t = (0.110.01*rank) if rank < 61 and t = 0.5 if rank > = 61, where: table_score – score in general statistics, nominal_task_score – nominal score for given problem (proportional to its difficulty), rank  your position in the table of results for the given problem.
 For problems of the challenge type: table_score = (nominal_task_score*your_score)/max_score, where table_score – score in general statistics, nominal_task_score – nominal score for given problem (proportional to its difficulty), your_score – score received by you for the given problem, max_score – current best score for given problem. Solutions are ordered by score and in case of equal score, the higher position will be awarded to the participant, who sent the solution earlier. Solutions which have earned zero score are not taken into consideration when calculating statistics.
 Organizers of the contest reserve the right to change contest rules in case of need, or to take into account circumstances not considered in the rules.