Assuming the controller inputs are synchronous you could do this with Max internal objects [thresh 0] and [mean]:
<pre><code>
----------begin_max5_patcher----------
521.3ocyWF0aqBBEG+Y8Sggm81fXQq6qxxxB0RWYQACh61aV128Kbvt0s15L
MZSeACGNx+yOwyIGdOL.sVsm2hhdH5wnff2CCB.SNCA8yCP0r8kUrVvMz1Jk
rqFE6WR0Yp3Fy+Z398.ghiPqYxWPQO06RCyTtSHe4YMuz38JIit.GGQVhcOn
vHgr.+46rUoqYfyY8VrZJjVoffH4Ki9..rR5sJ1.ApZ8q+Io.8YTnY0bCW+L
WxVWAgK1szGggtg3QheoptlKMG1VCeODlHgjhtLvjbfwLXL0yK9HdGAc3yPW
NZRIX4PDPnyAAYSKAoCPPRdwhb5zi.cZQfLDBoyxgvxokfjAHnXVxCRuF.j7
+Ze4Sh+sWrzlsxmqlzS+ZZtGRRwB5OJq8M7HmEujyfWx8Bd9Z.SMd36D7RVM
GmdE2KzkNGGdqtSnqXNN5xmP3p4L4uvWrq3oYLMNkT.ORKNowoqqMIxDBpYm
l2tKBe4NDGCf9dBojgAb70XNFPXuPUB4Oa7EhGm8uScqpSWdH58ethi9Jh1v
aMBIyHTxi7w04oyoy9gcrBYq7OBklBgv2HgJtQ5r5FoS9s5.ZD5PNQG+e5rl
l2351dmAIrYxupztoqhgoBoeJbcKjl+l3f+TvBSayTM1zzNMDVn8Y9aKfpUa
3ZYm.x7BcvYkDpRHsW3psg44.JlD9Q3+Az1ZHEH
-----------end_max5_patcher-----------
</code></pre>