program average_of_extremes;

var

 x: array [1..12] of integer;

 i, max, min, sum: integer;

begin

 randomize;

 max := -25;

 min := 25;

 sum := 0;

 for i := 1 to 12 do

 begin

   x[i] := random(51) - 25;

   if x[i] > max then max := x[i];

   if x[i] < min then min := x[i];

 end;

 sum := max + min;

 writeln(sum div 2);

end.