In a series of numbers 2, 2, 4, 8, 2, ..., starting from the third number, each number is the unit digit of the product of the two numbers before it. According to this rule, what is the 2004th number in this column of numbers?
在一列数2、2、4、8、2、…中，从第3个数开始，每个数都是它前面两个数的乘积的个位数字．按这个规律，这列数中的第2004个数是多少．
<result>6</result>