Some natural numbers (except 0) are both square numbers and cube numbers. (Note: A square number can be written as the product of two identical natural numbers, and a cubic number can be written as the product of three natural numbers). Such as: 1=1*1=1*1*1, 64=8*8=4*4*4. Then, among the natural numbers less than 1000, how many such numbers are there?
有一些自然数(0除外)既是平方数，又是立方数．(注：平方数可以写成两个相同的自然数的乘积，立方数可以写成三个自然数的乘积)．如：1=1*1=1*1*1,64=8*8=4*4*4．那么，1000以内的自然数中，这样的数有多少个．
<result>3</result>