var n,i,j,ans,cnt:longint;
    a:array[1..100000]of longint;
    u:array[1..100000]of boolean;
begin
 readln(n);
 fillchar(u,sizeof(u),true);
 for i:=1 to n do read(a[i]);
 for i:=31 downto 0 do begin
  cnt:=0;
  for j:=1 to n do begin
  if (a[j]>>i mod 2=1)and(u[j]) then inc(cnt);
  end;
  if cnt>=2 then begin
    ans:=ans+(1<<i);
    for j:=1 to n do
     if a[j]>>i mod 2=0 then u[j]:=false;
  end;
 end;
 writeln(ans);
 close(input);
 close(output);
end.