#include <cstdio>
#include <algorithm>

using namespace std;

const int NMAX = 1 << 20;
const int P[] = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997, 1009};

int N, Vmax;
bool F[NMAX];

void read(void) {
	FILE *fin = fopen("pairs.in", "rt");
	int i, u;

	fscanf(fin, " %d", &N);

	for (i = 0; i < N; ++i) {
		fscanf(fin, " %d", &u);
		F[u] = true;
		Vmax = max(Vmax, u);
	}

	fclose(fin);
}

int main(void) {

	read();

	int i, j, c, cnt;
	long long rez, aux;
	bool t, ok;

	rez = (long long) N * (N - 1) / 2;

	for (i = 2; i <= Vmax; ++i) {

		t = false; ok = true;
		for (c = i, j = 0; P[j] * P[j] <= c && ok; ++j)
			if (c % P[j] == 0) {
				c /= P[j];
				t = !t;
				if (c % P[j] == 0)
					ok = false;
			}

		if (!ok) continue;

		for (cnt = 0, j = i; j <= Vmax; j += i)
			if (F[j]) ++cnt;

		if (c != 1) t = !t;

		aux = ((long long) cnt * (cnt - 1)) / 2;

//		printf("%d %d %lld\n", i, cnt, aux);

		if (t)
			rez -= aux;
		else
			rez += aux;
	}

	FILE *fout = fopen("pairs.out", "wt");

	fprintf(fout, "%lld\n", rez);

	fclose(fout);

	return 0;
}