let isCollision (abt1, abt2) =
    let (a1, b1, t1) = abt1
    let (a2, b2, t2) = abt2

    if a1 = a2 then
        false
    else
        let g1 = t1 + b2
        let g2 = t2 + b1
        g1 = g2

let solve n (abtArr: (int * int * int) array) =
    seq {
        for i in 0 .. (n - 2) do
            for j in (i + 1) .. (n - 1) ->
                (abtArr.[i], abtArr.[j])
    }
    |> 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"