program discount;
uses wincrt;
var
average:integer;
begin
writeln ('average=');
read(average);
        if(average<=12) then
                writeln ('discount=0');

         if (average>12) and (average<=15)then
             writeln('discount=10');
         if (average>15)and(average<=17)then
             writeln('discount=20');
         if(average>17)and(average<=19)then
             writeln('discount=30');
         if(average=20)then
            writeln('discount=40');
readln
end.