说明：  描述 　　教练员 A、B 和 C 将要从编号为1到n的队员中挑选自己的队员。为公平起见，每个教练都根据自己的喜好程度将队员排序；你负责根据以下规则为他们分配队员。 　　你拿到的数据是 a、b、c 三个数组，表示三个教练对队员的喜好程度排序，每个数组都是数字 1 到 n 的一个排列，下标越小表示教练越喜欢该队员（例如教练 A 最喜欢编号为 a[0] 的队员，其次是编号为 a[1] 的队员）。你的分组规则是，从还未被分配的队员中找一个教练A最喜欢的队员分到 A 组；然后，在未分配的队员中分配教练B最喜欢的队员到 B 组；然后是教练 C；再是教练 A、B......依次类推直到所有队员分配完毕。 　　现在队员 k 希望知道自己被分配给哪位教练，请你来告诉他。 输入 　　共 5 行。 　　第 1 行包含一个整数 n。 　　第 2 至 4 行依次是数组 a、b 和 c，每行都是整数 [1, n] 的一个排列。 　　第 5 行包含一个整数 k。 输出 　　仅一个字符，A、B 或 C，表示队员 k 被分配给哪位教练。
(description Trainers A, B and C will pick their team members from among those numbered 1 to n. To be fair, each coach sorts team members according to their preference; you are responsible for assigning team members to them according to the following rules. You get the data is a, b, c three arrays, said three coaches on the level of preferences of players, each array is a number from 1 to n per array, the smaller subscript coach said the more like the player ( For example, coach A prefers player a [0], followed by player a [1]). Your grouping rule is to find a coach A from the unassigned team members, and then to group B the unassigned team member's favorite team member B. Then, coach C ; Then coaches A, B ... and so on until all players have been assigned. Now player k wants to know which coach he is assigned to. Please tell him.)