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 j in range(N):
        if i + x[j] <= K:
            dp[i+x[j]] += dp[i]
            dp[i+x[j]] %= 10**9 + 7

print(dp[K])