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

dp = [0 for _ in range(K+1)]
dp[0] = 1
mod = 1000000007

for k in range(1, K+1):
    for x in X:
        if k-x < 0:
            break
        dp[k] += dp[k-x] 
        dp[k] %= mod

print(dp[K])