MOD = 10**9 + 7

K = int(input())
N = int(input())
x = list(map(int, input().split()))
x.sort(reverse=True)  # Sort in descending order to break early

dp = [0] * (K + 1)
dp[0] = 1  # Base case: one way to stay at step 0

for k in range(1, K + 1):
    total = 0
    for xi in x:
        if xi > k:
            continue  # Skip steps larger than current k
        total += dp[k - xi]
        if total >= MOD:
            total -= MOD
    dp[k] = total % MOD

print(dp[K] % MOD)