#include <stdio.h>

int factorize(int n, int p[], int m[])
{
	int i, k;
	for (i = 2, k = 0; i * i <= n; i++) {
		if (n % i != 0) continue;
		p[k] = i;
		for (m[k] = 0; n % p[k] == 0; m[k]++, n /= p[k]);
		k++;
	}
	if (n > 1) {
		p[k] = n;
		m[k++] = 1;
	}
	return k;
}

int main()
{
	int i, N, M, A;
	scanf("%d %d", &N, &M);
	
	int h, j, k, l[101], ll[101],  m[101], p[101], tmp, tmpp, count[1000001] = {};
	long long ans = 0, memo[1000001];
	for (i = 1; i <= N; i++) memo[i] = -1;
	for (i = 1; i <= M; i++) {
		scanf("%d", &A);
		if (memo[A] != -1) {
			ans += memo[A];
			continue;
		} else memo[A] = 0;
		
		k = factorize(A, p, m);
		for (j = 0, tmp = A; j < k; j++) l[j] = m[j];
		while (tmp > 1) {
			count[tmp] = A / tmp;
			for (j = 0, tmpp = tmp; j < k; j++) ll[j] = l[j];
			while (tmpp < A) {
				for (h = 0; h < k && ll[h] == m[h]; h++);
				if (h == k) break;
				for (ll[h]++, tmpp *= p[h--]; h >= 0; ll[h] = l[h], h--) {
					for (j = l[h]; j < m[h]; j++) tmpp /= p[h];
				}
				count[tmp] -= count[tmpp];
			}
			memo[A] += (long long)(tmp - 1) * count[tmp];
			
			for (h = 0; h < k && l[h] == 0; h++);
			for (l[h]--, tmp /= p[h--]; h >= 0; l[h] = m[h], h--) {
				for (j = 0; j < m[h]; j++) tmp *= p[h];
			}
		}
		ans += memo[A];
		
		for (j = 1, l[0] = 1, tmp = p[0]; j < k; j++) l[j] = 0;
		while (1) {
			count[tmp] = 0;
			for (h = 0; h < k && l[h] == m[h]; h++);
			if (h == k) break;
			for (l[h]++, tmp *= p[h--]; h >= 0; l[h--] = 0) {
				for (j = 0; j < m[h]; j++) tmp /= p[h];
			}
		}
	}
	
	printf("%lld\n", ans);
	fflush(stdout);
	return 0;
}