Xiaoqiang rides on the back of an ox to cross the river. There are six cows A, B, C, D, E, and Ji in total. It takes 1 minute for A ox to cross the river, 2 minutes for B ox to cross the river, 3 minutes for C ox to cross the river, and 3 minutes for D ox to cross the river. It takes 4 minutes for an ox to cross the river, 5 minutes for an ox to cross the river, and 6 minutes for an individual ox to cross the river. Only 3 oxen can cross the river at a time. How long will it take at least to drive all 6 oxen to the other side?
小强骑在牛背上过河，共有甲、乙、丙、丁、戊、己六头牛，甲牛过河要1分钟，乙牛过河要2分钟，丙牛过河要3分钟，丁牛过河要4分钟，戊牛过河要5分钟，己牛过河要6分钟，每次只能3头牛过河，要把6头牛都赶到对岸去，最少要几分钟？
<gadget id="calculator">6 + 1 + 4 + 1 + 2</gadget>
<output>14</output>

<result>14</result>