#include "bits/stdc++.h"
using namespace std;
#define mod 1000000007
#define dom 998244353
#define all(c) begin(c),end(c)
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
//template <typename T> bool &chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
//template <typename T> bool &chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; }
#define long long long
#define List vector
#define var auto
#define Count size()
#define Length size()
int dd[] = { 0, 1, 0, -1, 0 }; //→↓←↑

void solve()
{
	int K, N;
	scanf("%d%d", &K, &N);
	vector<int> X(N);
	for (int i = 0; i < N; ++i)
	{
		scanf("%d", &X[i]);
	}

	vector<int> dp(K + 1);
	dp[0] = 1;
	for (int i = 1; i <= K; ++i)
	{
		for (int j = 0; j < N && X[j] <= i; j++)
		{
			dp[i] += dp[i - X[j]];
			if (dp[i] > mod)dp[i] -= mod;
		}
	}
	printf("%d\n", dp[K]);
}

int main()
{
	//cin.tie(0);
	//ios::sync_with_stdio(false);
	solve();
	return 0;
}