program task27B;

var val, max2, max7, max14, max_prod, max_total, n, i: integer;

begin

max2 := -1;
max7 := -1;
max14 := -1;
max_total := -1;
max_prod := -1;

read(n);

for i:= 1 to n do begin
  read(val);

if (val mod 14 = 0) and (val > max14) then
  max14 := val
else if val > max_total then
  max_total:= val;

if (val mod 7 = 0) and (val mod 14 <> 0) and (val > max7) then
  max7 := val;

if (val mod 2 = 0) and (val mod 14 <> 0) and (val > max2) then
  max2 := val;

end;

max_prod := max14 * max_total;
if (max2 * max7 > max_prod) then
  max_prod := max2 * max7;

writeln(max_prod);

end.