MOD = 10**9 + 7

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

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

for k in range(1, K + 1):
    # Find the rightmost index where x[i] <= k using binary search
    left, right = 0, N
    while left < right:
        mid = (left + right) // 2
        if x[mid] > k:
            right = mid
        else:
            left = mid + 1
    # Now, left is the first index where x[i] > k, so valid x are 0..left-1
    for i in range(left):
        xi = x[i]
        if xi > k:
            continue
        dp[k] += dp[k - xi]
        if dp[k] >= MOD:
            dp[k] -= MOD

print(dp[K] % MOD)