#include <bits/stdc++.h>

using namespace std;

using ll = long long;

const ll MOD = 1000000007;

ll modpow(ll x, ll n, ll mod = MOD) {
    ll res = 1;
    while (n > 0) {
        if (n & 1) res = res * x % mod;
        x = x * x % mod;
        n >>= 1;
    }
    return res;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int K, n;
    cin >> K >> n;
    vector<int> x(n);
    for (int i = 0; i < n; i++) cin >> x[i];

    vector<ll> dp(K + 1, 0);
    dp[0] = 1;
    for (int i = 1; i <= K; i++) {
        for (int y : x) {
            if (i < y) break;
            (dp[i] += dp[i - y]) %= MOD;
        }
    }
    cout << dp[K] << endl;
    return 0;
}