defmodule Main do
  def main do
    1..(IO.read(:line)
        |> String.trim()
        |> String.to_integer())
    |> Enum.map(fn _ ->
      IO.read(:line)
      |> String.trim()
      |> String.split()
    end)
    |> solve
    |> IO.puts()
  end

  def solve(l) do
    l
    |> Enum.map(fn [a, b] ->
      [[bh, bm], [eh, em]] =
        [a, b]
        |> Enum.map(fn i ->
          i
          |> String.split(":")
          |> Enum.map(&String.to_integer/1)
        end)

      cond do
        bh > eh -> [bh - 24, bm]
        bh == eh && bm > em -> [bh, bm - 24 * 60]
        true -> [bh, bm]
      end
      |> (fn [bh, bm] -> eh * 60 + em - (bh * 60 + bm) end).()
    end)
    |> Enum.sum()
  end
end