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