Let $a$, $b$, $c$ be fixed positive integers. There are $a+b+c$ ducks sitting in a circle, one behind the other. Each duck picks either rock, paper, or scissors, with $a$ ducks picking rock, $b$ ducks picking paper, and $c$ ducks picking scissors. A move consists of an operation of one of the following three forms: [list] [*] If a duck picking rock sits behind a duck picking scissors, they switch places. [*] If a duck picking paper sits behind a duck picking rock, they switch places. [*] If a duck picking scissors sits behind a duck picking paper, they switch places. [/list] Determine, in terms of $a$, $b$, and $c$, the maximum number of moves which could take place, over all possible initial configurations.