K = int(input())
N = int(input())
X = list(map(int, input().split()))
dp = [[0]*K for _ in range(K)]
mod = 10**9 + 7
for x in X:
    if x < K:
        dp[0][x-1] = 1

ans = 0
for i in range(1,K):
    for j in range(X[0]*i,K):
        for x in X:
            if 0 <= j-x < K:
                dp[i][j] += dp[i-1][j-x]
                dp[i][j] %= mod
    ans += dp[i][-1]
    ans %= mod
print(ans)