#include <bits/stdc++.h>
using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, b, a) for(int i = (b) - 1; i >= (a); i--)
#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;


const int mod = 1e9 + 7;
void updAdd(int& a, int b)
{
	a += b;
	if(a >= mod)
		a -= mod;
}
void updSub(int& a, int b)
{
	a -= b;
	if(a < 0)
		a += mod;
}
int mult(int a, int b)
{
	return (LL)a * b % mod;
}
int binpow(int a, int n)
{
	int res = 1;
	while(n)
	{
		if(n & 1)
			res = mult(res, a);
		
		a = mult(a, a);
		n /= 2;
	}
	return res;
}
int inv(int x)
{
	return binpow(x, mod - 2);
}

int C(int n, int m)
{
	int ans = 1;
	FOR(i, 0, m)
	{
		ans = mult(ans, n - i);
		ans = mult(ans, inv(i + 1));
	}
	return ans;
}


int solve(int n, VI lens)
{
	n -= SZ(lens) - 1;
	FOR(i, 0, SZ(lens))
		n -= lens[i];
	
	if(n < 0)
		return 0;
	
	int cnt = 2 * SZ(lens) + 1;
	
	return C(n + cnt - 1, cnt - 1);
}

set<vector<PII>> calculated;
int solve(int n, vector<PII> lens)
{
	if(calculated.count(lens) == 1)
		return 0;
	calculated.insert(lens);
	
	int ans = 0;
	FOR(mask, 0, 1 << SZ(lens))
	{
		VI cur(SZ(lens));
		FOR(i, 0, SZ(lens))
		{
			if((mask >> i) & 1)
				cur[i] = lens[i].S;
			else
				cur[i] = lens[i].F;
		}
		int val = solve(n, cur);
		if(__builtin_popcount(mask) % 2 == 0)
			updAdd(ans, val);
		else
			updSub(ans, val);
	}
	return ans;
}


VI vals;

vector<PII> possible[4];

vector<PII> genVec;
int resRecalc = 0;

void rec(int pos, int sz, int n)
{
	if(pos == sz)
	{
		updAdd(resRecalc, solve(n, genVec));
		return;
	}
	for(auto val : possible[pos])
	{
		genVec.PB(val);
		rec(pos + 1, sz, n);
		genVec.pop_back();
	}
}


int recalc(int n, vector<PII> lens)
{
	resRecalc = 0;
	FOR(i, 0, SZ(lens))
	{
		possible[i].clear();
		
		
	}
	rec(0, SZ(lens), n);
	return resRecalc;
}


int main()
{
	ios::sync_with_stdio(0); 
	cin.tie(0);
	cout << fixed << setprecision(15);
	
	int n, k;
	cin >> n >> k;
	VI a(k);
	FOR(i, 0, k)
		cin >> a[i];
	
	FOR(mask, 1, 1 << k)
	{
		int sum = 0;
		FOR(i, 0, k)
			if((mask >> i) & 1)
				sum += a[i];
		vals.PB(sum);
		vals.PB(sum + 1);
	}
	sort(ALL(vals));


	int ans = 0;
	
	VI idx(k);
	iota(ALL(idx), 0);
	
	
	do{
		FOR(mask, 0, 1 << (k - 1))
		{
			vector<PII> lens = {MP(a[idx[0]], a[idx[0]] + 1)};
			FOR(i, 0, k - 1)
			{
				if((mask >> i) & 1)
				{					
					lens.back().F = max(lens.back().F, a[idx[i + 1]]);
					lens.back().S += a[idx[i + 1]];
				}
				else
					lens.PB(MP(a[idx[i + 1]], a[idx[i + 1]] + 1));
			}
			updAdd(ans, recalc(n, lens));							
		}
		
	}while(next_permutation(ALL(idx)));
	
	cout << ans << endl;
	
	
	
	
	
	
	return 0;
}