#include <iostream>
#include <vector>
using namespace std;

const int MOD = 1e9 + 7;

int main() {
    int K, N;
    cin >> K >> N;
    
    vector<int> x(N);
    for (int i = 0; i < N; ++i) {
        cin >> x[i];
    }
    
    vector<int> dp(K + 1, 0);
    dp[0] = 1;

    for (int i = 0; i < K; ++i) {
        for (int j = 0; j < N; ++j) {
            int a = i + x[j];
            if (a > K) {
                break;  // a > K ならループを抜ける
            }
            dp[a] += dp[i];
            dp[a] %= MOD;
        }
    }

    cout << dp[K] << endl;

    return 0;
}