In the figure above, three sires are braided. That is， by sarting in the order A,B,C, the outer lt wire A is brought over wire B to the middle position, forming the order to the new middle position position shown in step 2, and so on, alternately bringing each new lt and each new right wire to the middle. At that numbered step does the braid first repeat the original order A B C.?

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题干不是给出了前2步 START ABC STEP1 BAC STEP2 BCA 那么以此类推,按照上面的顺序换CB的位置（一次置换两根绳之间的位置，你只要看是发生在一二还是二三之间就好） STEP3 CBA STEP4 CAB STEP5 ACB STEP6 ABC

In the figure above, three sires are braided. That is， by sarting in the order A,B,C, the outer lt wire A is brought over wire B to the middle position, forming the order to the new middle position position shown in step 2, and so on, alternately bringing each new lt and each new right wire to the middle. At that numbered step does the braid first repeat the original order A B C.?

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