- Time limit: 1.00 s
- Memory limit: 512 MB
Given a list of n positive integers, your task is to count the number of pairs of integers that are coprime (i.e., their greatest common divisor is one).
The first input line has an integer n: the number of elements.
The next line has n integers x_1,x_2,\dots,x_n: the contents of the list.
Print one integer: the answer for the task.
- 1 \le n \le 10^5
- 1 \le x_i \le 10^6
8 5 4 20 1 16 17 5 15