program groupa(input,output);

var
  n,i,j,l,r,ans,tmp:longint;
  gp:array[1..10000]of longint;

begin
  assign(input,'groupa.in');
  reset(input);
  assign(output,'groupa.out');
  rewrite(output);

  readln(n);

  for i:=1 to n do
    read(gp[i]);

  readln(l,r);

  for i:=1 to n do
    if gp[i]<l then
    begin
      for j:=1 to n do
        if gp[j]>r then
        begin
          tmp:=gp[j]-l;
          if l-gp[i]<tmp then
            tmp:=l-gp[i];

          gp[j]:=gp[j]-tmp;
          gp[i]:=gp[i]+tmp;
          ans:=ans+tmp;

          if gp[i]>=l then
            break;
        end;

      for j:=1 to n do
        if gp[j]>l then
        begin
          tmp:=gp[j]-l;
          if l-gp[i]<tmp then
            tmp:=l-gp[i];

          gp[j]:=gp[j]-tmp;
          gp[i]:=gp[i]+tmp;
          ans:=ans+tmp;

          if gp[i]>=l then
            break;
        end;
    end
    else if gp[i]>r then
    begin
      for j:=1 to n do
        if gp[j]<l then
        begin
          tmp:=r-gp[j];
          if gp[i]-r<tmp then
            tmp:=gp[i]-r;

          gp[j]:=gp[j]+tmp;
          gp[i]:=gp[i]-tmp;
          ans:=ans+tmp;

          if gp[i]<=r then
            break;
        end;

      for j:=1 to n do
        if gp[j]<r then
        begin
          tmp:=r-gp[j];
          if gp[i]-r<tmp then
            tmp:=gp[i]-r;

          gp[j]:=gp[j]+tmp;
          gp[i]:=gp[i]-tmp;
          ans:=ans+tmp;

          if gp[i]<=r then
            break;
        end;
    end;

  for i:=1 to n do
    if (gp[i]>r)or(gp[i]<l) then
      ans:=-1;

  writeln(ans);

  close(input);
  close(output);
end.