#include <bits/stdc++.h>
using namespace std;
int w, n, s[30005], ans, l = 1;

int main() {
	//freopen("group.in","r",stdin);
	//freopen("group.out","w",stdout);
	scanf("%d%d", &w, &n);
	for (int i = 1; i <= n; i++)
		scanf("%d", &s[i]);
	sort(s + 1, s + n + 1);
	int r = n;
	while (l <= r)
		(s[l] + s[r] <= w) ? l++, r--, ans++ : r--, ans++;
	printf("%d", ans);
	return 0;
}