Program z21; Var n, days, a:integer; b,c:set of integer;Begin write ('Введите номер месяца - '); readln (n); write ('Введите признак года - '); readln (a); b:= [1,3,5,7,8,10,12]; c:= [3,6,9,11]; if (n in b) then days:= 31; if (n in c) then days:= 30; if (n = 2) then if (a = 1) then days:= 29 else days:= 28; writeln('Кол-во дней = ', days);End.