- Time limit: 1.00 s
- Memory limit: 512 MB
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
- 1 \le n \le 5000
- 1 \le x_i \le 5000
Example
Input:
4 2 2 3 6
Output:
4