F# 检索最常用的名称

我想不起来。如何找到最常用的名称，例如

type person = {name:string; surname:string}

let persons=[{name:"Jack";surname:"YYY"};
             {name:"Joe";surname:"XYX"};
             {name:"Jack";surname:"XXY"}]

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这听起来像是一个家庭作业问题。。。

// You have to use '=' instead of ':' between field names and field values
let persons = 
    [ {name = "Jack"; surname = "YYY"};
      {name = "Joe"; surname = "XYX"};
      {name = "Jack"; surname = "XXY"} ]

// val it : string = "Jack"
persons |> Seq.countBy (fun {name = s} -> s)
        |> Seq.maxBy snd
        |> fst