关于分组后获取桶总数的问题

这是我的数据源。

[

  {

      "buyer_id_std" : 35444337,

      "seller_id_std" : 3587575,

      "date" : "2021-02-24T00:00:00"

  },

  {

      "buyer_id_std" : 35444337,

      "seller_id_std" : 75848633,

      "date" : "2021-01-20T00:00:00"

  },

  {

      "buyer_id_std" : 35444337,

      "seller_id_std" : 25308769,

      "date" : "2021-01-19T00:00:00"

  },

  {

      "buyer_id_std" : 35444337,

      "seller_id_std" : 25308769,

      "date" : "2021-01-19T00:00:00"

  },

  {

      "buyer_id_std" : 35444337,

      "seller_id_std" : 74256954,

      "date" : "2021-01-19T00:00:00"

  },

  {

      "buyer_id_std" : 35444337,

      "seller_id_std" : 65945090,

      "date" : "2021-01-20T00:00:00"

  },

  {

      "buyer_id_std" : 35444337,

      "seller_id_std" : 74256954

      "date" : "2021-01-19T00:00:00"

  },

  {

      "buyer_id_std" : 35444337,

      "seller_id_std" : 2374066,

      "date" : "2021-01-20T00:00:00"

  },

  {

      "buyer_id_std" : 35444337,

      "seller_id_std" : 64505236,

      "date" : "2021-01-19T00:00:00"

  },

  {

      "buyer_id_std" : 35444337,

      "seller_id_std" : 78976932,

      "date" : "2021-01-19T00:00:00"

  }

]

这个是我的查询语句

GET trade/_search

{

  "query": {

    "bool": {

      "filter": [

        {

          "term": {

            "buyer_id_std": 35444337

          }

        },

        {

          "range": {

            "date": {

              "gte": "2020-09-06T00:00:00Z",

              "lte": "2021-09-06T00:00:00Z"

            }

          }

        }

      ]

    }

  },

  "aggs": {

    "group_by_partner": {

      "terms": {

        "field": "seller_id_std",

        "size": 200000

      },

      "aggs": {

        "min_date": {

          "min": {

            "field": "date"

          }

        },

        "max_date": {

          "max": {

            "field": "date"

          }

        },

        "mdate": {

          "bucket_selector": {

            "buckets_path": {"md": "max_date"},

            "script": "params.md > 1601164800000L"

          }

        },

        "bucket_field": {

          "bucket_sort": {

            "from": 0,

            "size": 2

          }

        }

      }

    },

    "sum_partner": {

      "stats_bucket": {

        "buckets_path": "group_by_partner>_count"

      }

    }

  },

  "size": 0,

  "track_total_hits": true

}

这个语句查询的结果是

{

  "took" : 46,

  "timed_out" : false,

  "_shards" : {

    "total" : 61,

    "successful" : 61,

    "skipped" : 0,

    "failed" : 0

  },

  "hits" : {

    "total" : {

      "value" : 10,

      "relation" : "eq"

    },

    "max_score" : null,

    "hits" : [ ]

  },

  "aggregations" : {

    "group_by_partner" : {

      "doc_count_error_upper_bound" : 0,

      "sum_other_doc_count" : 0,

      "buckets" : [

        {

          "key" : 74256954,

          "doc_count" : 155,

          "max_date" : {

            "value" : 1.6308864E12,

            "value_as_string" : "2021-09-06T00:00:00.000Z"

          },

          "min_date" : {

            "value" : 1.6020288E12,

            "value_as_string" : "2020-10-07T00:00:00.000Z"

          },

          "count" : {

            "value" : 1

          }

        },

        {

          "key" : 2374066,

          "doc_count" : 108,

          "max_date" : {

            "value" : 1.6308E12,

            "value_as_string" : "2021-09-05T00:00:00.000Z"

          },

          "min_date" : {

            "value" : 1.6073856E12,

            "value_as_string" : "2020-12-08T00:00:00.000Z"

          }

        }

      ]

    },

    "sum_partner" : {

      "count" : 2,

      "min" : 108.0,

      "max" : 155.0,

      "avg" : 131.5,

      "sum" : 263.0

    }

  }

}

我想要的结果是能统计到桶的个数，如上结果，我需要的桶的总个数是8个而不是2个。
这里不能使用 

"count": {"cardinality": {"field": "

seller_id_std"}},

因为这里统计的是总的桶数，而我需要的是桶过滤后的总数, 也就是下面这段代码过滤后的总数

"mdate": {

    "bucket_selector": {

    "buckets_path": {"md": "max_date"},

    "script": "params.md > 1601164800000L"

    }

}

请求各位大佬出出主意