use List::Util qw/sum/;
use SQL::Abstract;
-use constant CONTEST_PUBLIC_COLUMNS => [qw/id name description start stop owner/];
use constant PROBLEM_PUBLIC_COLUMNS => [qw/id author writer level name owner private timeout olimit value/];
-use constant USER_PUBLIC_COLUMNS => [qw/id admin name town university country level/];
use constant JOBS_PER_PAGE => 50;
my %statements = (