After expanding the four-digit \overline{2abc} by 3 times, it becomes another four-digit \overline{abc8}. Find the number of \overline{abc}=.
把四位数\overline{2abc}扩大3倍后便成了另一个四位数\overline{abc8}，求\overline{abc}=多少．
<result>2_856</result>