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

DP = [0]*(K+1)
DP[0] = 1
for i in range(K):
    for xx in x:
        if i+xx <= K:
            DP[xx+i] = (DP[xx+i] + DP[i]) % (10**9+7)
print(DP[K]%(10**9+7))