Weiwei and Lele play a game of "rock, scissors, cloth". Two people use the same number of stones to record, and lose one stone to the other. They played many games, among which Weiwei won 3 times, and Lele added 9 stones. How many games have they played at least.
惟惟和乐乐玩"石头、剪子、布"的游戏．两人用同样多的石子做记录，输一次给对方一颗石子．他们做了许多次游戏，其中惟惟胜了3次，乐乐增加了9颗石子．他们至少做了多少次游戏．
<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">9 + 6</gadget>
<output>15</output>

<result>15</result>