请输入年，月，然后告诉该月有多少天。

var

year,month,days:integer;

begin

readln(year,month);

if (year mod 400=0) or (year mod 4=0) and (year mod 100<>0) then

case month of

1,3,5,7,8,10,12:days:=31;

4,6,9,11:days:=30;

2:days:=29;

end

else case month of

1,3,5,7,8,10,12:days:=31;

4,6,9,11:days:=30;

2:days:=28;

end;

writeln(days);

end.