#5526. Square Subsets
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Square Subsets
Square Subsets
Given an array of n integers, count the number of subsets whose elements' product is a square number. Also count the empty subset with product equal to one.
Input
The first line has an integer n: the size of the array. The next line has n integers x_1, x_2,\dots, x_n: the contents of the array.
Output
Print one integer: the answer to the problem modulo 10^9 + 7.
Constraints
Example
Input
4
2 2 3 6
Output
4