let ``No.712 赤旗``() =
  let n ,m =
    stdin.ReadLine().Split(' ')
    |> Array.map (int)
    |> fun args -> args.[0], args.[1]
  
  [1..n]
  |> List.sumBy (fun i ->
    let a = stdin.ReadLine()
    a.Replace("R", "").Length
      )
  |> stdout.WriteLine      
  ()
``No.712 赤旗``()