#include<iostream>
#include<fstream>
using namespace std;
ifstream f("pairs.in");
ofstream g("pairs.out");
long n, a[101], x, y,i, c,j;
int prim(int n, int m)
{
	while (n != m)
		if (n > m)
			n = n - m;
		else
			m = m - n;
	return n;
}
int main()
{
	f >> n;
	for (i = 1; i <= n; i++)
		f >> a[i];
	for (i = 1; i <= n; i++)
	{
		for (j = 1; j <= n; j++)
			if (a[i] != a[j] && prim(a[i], a[j]) == 1)
		c++;
	}
	cout << c / 2;
}