How to aggregate by group in mongoldb?

I have a collection named rice. Im making a pipeline to group and count the number of rice based on average from two places. Next I am calculating based on the following:

1. It has several sizes if the size under 3, it will be in the 1st group and the number of rice counted.
2. If the size is 3 and below 10, it will in second group and the number of rice counted.
3. If the size is 10 and above, it will in third group and the number of rice counted. I have used the code in the following :

db.rice.aggregate([
    { $group: { _id: ["0","3","10"],
                rice_title_avg_rice_size: {
                "tittle": {$title},
                "average_size": {$avg:["$size_A","$size_B"]},
                num_rice: {$count: {}
                }
                }
              }
            {"_id.1":{$lt:3}, "_id.2":{$gte:3, $lt:10 }, "_id.3":{$gt:10}}
    },
    { $sort: { _id: -1 } }
])