\[\begin {array} {1 1} (1)\;m_1 < m_2 < m_3 < m_4 & \quad (2)\;m_4 < m_3 < m_2 < m_1 \\ (3)\;m_3 < m_2 < m_4 < m_1 & \quad (4)\;m_3 < m_1 < m_2 < m_4 \end {array}\]