   .addSize([1024, 200], [[970, 250], [970, 90], [728, 90], [9,7]]) //Desktop
                                              .addSize([768, 200], [728, 90]) //Tablet
                                              .addSize([500, 0], [[320, 100], [320, 50]]) //Mobile
                                              .build();
                                      gptAdSlots[3] = googletag.defineSlot(dfp_sitePage, [320, 100], 'adpos_bottomA')
                                              .defineSizeMapping(size