#include<set>
#include<vector>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>

using namespace std;

const int M = 11;

int n, m, a[M];

vector<vector<int> > nst;

vector<int> tmp;

set<pair<vector<int>, vector<int> > > mem;

void go(vector<int> &cst, int b, int s) {
	vector<vector<int> > st;
	vector<int> init;
	init.push_back(b);
	init.push_back(s);
	st.push_back(init);
	vector<int> bak = cst;
	reverse(bak.begin(), bak.end());
	for (int i = 0; i < (int)cst.size(); ++i) {
		vector<vector<int> > nst;
		bak.pop_back();
		for (int j = 0; j < (int)st.size(); ++j) {
			if (j && st[j] == st[j - 1]) {
				continue;
			}
			vector<int> tmp = st[j];
			if (mem.count(make_pair(tmp, bak))) {
				continue;
			}
			mem.insert(make_pair(tmp, bak));
			int b = tmp[tmp.size() - 2],
				s = tmp[tmp.size() - 1];
			tmp.pop_back(), tmp.pop_back();
			for (int k = max(0, cst[i] - s); k <= (int)cst[i] && k <= b; ++k) {
				vector<int> ntmp = tmp;
				if (k == 0 || k == cst[i]) {
					ntmp.push_back(cst[i]);
				} else {
					ntmp.push_back(k);
					ntmp.push_back(cst[i] - k);
				}
				sort(ntmp.begin(), ntmp.end());
				ntmp.push_back(b - k);
				ntmp.push_back(s - (cst[i] - k));
				nst.push_back(ntmp);
			}
		}
		sort(nst.begin(), nst.end());
		st = nst;
	}
	for (int i = 0; i < (int)st.size(); ++i) {
		if (i && st[i] == st[i - 1]) {
			continue;
		}
		vector<int> tmp = st[i];
		tmp.pop_back();
		tmp.pop_back();
		nst.push_back(tmp);
	}
}

int main() {
	scanf("%d%d", &n, &m);
	for (int i = 0; i < m; ++i) {
		scanf("%d", a + i);
	}
	vector<vector<int> > st;
	vector<int> init;
	init.push_back(n);
	st.push_back(init);
	for (int i = 0; i < m; ++i) {
		mem.clear();
		cout << i << ' ' << st.size() << endl;
		for (int j = 0; j < (int)st.size(); ++j) {
			if (j && st[j] == st[j - 1]) {
				continue;
			}
			go(st[j], a[i], n - a[i]);
		}
		sort(nst.begin(), nst.end());
		st = nst;
		nst.clear();
	}
	int ans = 0;
	for (int i = 0; i < (int)st.size(); ++i) {
		int cnt = 0;
		for (int j = 0; j < (int)st[i].size(); ++j) {
			if (st[i][j] == 1) {
				++cnt;
			}
		}
		ans = max(ans, cnt);
	}
	printf("%d\n", ans);
	return 0;
}