program groupa;
var
  i,j,k,n:longint;
  a:array[1..50]of longint;
  l,r,o,p:longint;
  max:longint;
begin
  assign(input,'groupa.in');
  reset(input);
  assign(output,'groupa.out');
  rewrite(output);
  readln(n);
  max:=0;
  for i:=1 to n do
  begin
    read(a[i]);
    max:=max+a[i];
  end;
  readln;
  readln(l,r);
  if (max<l*n) or (max>r*n) then
  begin
    writeln('-1');
    close(input);
    close(output);
    halt;
  end;
  o:=0;
  p:=0;
  for i:=1 to n do
    if a[i]<l then o:=o+l-a[i]
    else if a[i]>r then p:=p+a[i]-r;
  if o>p then writeln(o)
  else writeln(p);
  close(input);
  close(output);
end.