import sys
sys.setrecursionlimit(10**7)
mod = 10**9+7

def convolution(A, B):
    la = len(A)
    lb = len(B)
    res = [0]*(la+lb-1)
    for i, a in enumerate(A):
        for j, b in enumerate(B):
            res[i+j] += a*b
            res[i+j] %= mod
    return res

def poly_mod(X, Q):
    a = len(X)
    b = len(Q)
    if a < b:
        return X
    for i in range(a-b, -1, -1):
        d = X[i+b-1]
        for j, q in enumerate(Q):
            X[i+j] -= q*d
            X[i+j] %= mod
    return X[:b-1]

def poly_pow(C, n, Q):
    if n == 1:
        return C
    d = len(C)
    if n%2:
        res = convolution(poly_pow(C, n-1, Q), C)
    else:
        T = poly_pow(C, n//2, Q)
        res = convolution(T, T)
    res = poly_mod(res, Q)
    return res
        
#[x^n]P/Qを求める
def poly_coef(Q, P, n):
    C = [-q for q in Q[1:]]
    inv = pow(Q[-1], mod-2, mod)
    norm_Q = [q*inv%mod for q in Q]
    X = poly_pow(C, n, norm_Q)
    res = convolution(X, P)
    res = poly_mod(res, norm_Q)
    return res[0]

k = int(input())
n = int(input())
A = tuple(map(int, input().split()))
Q = [0]*(A[-1]+1)
Q[0] = 1
for a in A:
    Q[a] = -1
P = [1]
ans = poly_coef(Q, P, k)
print(ans)