#include <iostream>
#include <algorithm>
using namespace std;
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
const int mod = 1000000007;
int K, N, M, X[100009], Y[100009]; long long dp[100009];
int main() {
	cin.tie(0);
	ios_base::sync_with_stdio(false);
	cin >> K >> N;
	int mx = 0;
	for (int i = 0; i < N; ++i) {
		cin >> X[i];
		if (X[i] > K) {
			N = i;
			break;
		}
	}
	if (N * 2 <= K) {
		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]];
			}
			dp[i] %= mod;
		}
		cout << dp[K] << endl;
	}
	else {
		for (int i = 1; i <= K; ++i) {
			if (!binary_search(X, X + N, i)) {
				Y[M++] = i;
			}
		}
		long long sum = 1;
		dp[0] = 1;
		for (int i = 1; i <= K; ++i) {
			dp[i] = sum;
			for (int j = 0; j < M && Y[j] <= i; ++j) {
				dp[i] -= dp[i - Y[j]];
			}
			dp[i] %= mod;
			sum += dp[i];
		}
		cout << dp[K] << endl;
	}
	return 0;
}