[{offices:[{ips:[]}],analytics:{visits:{amounts:[],dates:[]}}}]

db.collection.update({},[{$set:{"analytics.visits.amounts":{$concatArrays:["$analytics.visits.amounts",[{$reduce:{input:"$offices",initialValue:0,in:{$sum:[{$size:"$$this.ips"},"$$value"]}}}]]},"analytics.visits.dates":{$concatArrays:["$analytics.visits.dates",[new Date()]]},}}],{"multi":false,"upsert":false})