procedure produs(n:integer; var p:integer);
begin
var a:array of integer;
var i:byte;
p:=1;
setlength(a,n);
for i:=0 to n-1 do read(a[i]);
for i:=0 to n-1 do if (a[i]<0) and (a[i] mod 3 = 0) then p*=a[i];
end;
var n,p:integer;
begin
read(n);
produs(n,p);
writeln(p);
end.