#include <stdio.h>

int x[100100], stieve[1000100], cnt[1000100];
bool is[1000100];

int main()
{
	int i, j, N, vmax = -1;
	
	freopen("pairs.in", "r", stdin);
	freopen("pairs.out", "w", stdout);
	
	scanf("%d", &N);
	for (i = 1; i <= N; i ++)
	{
		scanf("%d", &x[i]);
		if (x[i] > vmax)
			vmax = x[i];
		is[x[i]] = true;
	}
	
	for (i = 2; i <= vmax; i ++)
		if (stieve[i] == 0)
			for (j = i; j <= vmax; j = j + i)
				stieve[j] ++;
	
	for (i = 2; i <= vmax; i ++)
		for (j = i; j <= vmax; j = j + i)
			if (is[j])
				cnt[i] ++;
			
	long long ans = 1LL * N * (N - 1) / 2;
	
	for (i = 2; i <= vmax; i ++)
		if (stieve[i] % 2 == 0)
			ans = ans + 1LL * cnt[i] * (cnt[i] - 1) / 2;
		else
			ans = ans - 1LL * cnt[i] * (cnt[i] - 1) / 2;
		
	printf("%lld", ans);
	return 0;
}