问道菜鸟数学题,请好心人指点

For all x, x is positive integer,"2-height" is defined to be the greatest nonnegative n of x,what is the greatest number of 2-height when 2" is the factor of x?

2

12

40

76

90

feifei宝典里面的题,感觉都不是人类的语言了,请哪位好心人指点一下?

2-height 就是 2^n 的那个n

2=2^1

12=2^2*3

40=2^3*5

76=2^2*19

90=2*45 当然是40的最大 是3啊