let isCollision (abt1, abt2) =
    let (_, b1, t1) = abt1
    let (_, b2, t2) = abt2
    let g1 = t1 + b2
    let g2 = t2 + b1
    g1 = g2

let solve n (abtArr: (int * int * int) array) =
    let (abtArr1, abtArr2) = Array.partition (fun (a1, _, _) -> a1 = 0) abtArr
    seq {
        for i in 1 .. (Array.length abtArr1) do
            for j in 1 .. (Array.length abtArr2) ->
                (abtArr1.[i - 1], abtArr2.[j - 1])
    }
    |> Seq.filter isCollision
    |> Seq.length

let () =
    let n = stdin.ReadLine() |> int
    let abtArr =
        seq {
            for i in 1 .. n ->
                stdin.ReadLine().Split() |> Array.map int |> fun arr -> (arr.[0], arr.[1], arr.[2])
        } |> Seq.toArray

    solve n abtArr |> printfn "%d"