MOD = 10**9 + 7

K = int(input())
N = int(input())
x = list(map(int, input().split()))

# Filter out steps larger than K and sort them
x = [xi for xi in x if xi <= K]
x.sort()

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

for k in range(1, K + 1):
    for xi in x:
        if xi > k:
            break  # Since x is sorted, no need to check further
        dp[k] += dp[k - xi]
        dp[k] %= MOD

print(dp[K] % MOD)