import sys

import numpy as np

sys.setrecursionlimit(10 ** 9)

K = int(input())

N = int(input())

X = np.array(list(map(int, input().split())))


P = 10 ** 9 + 7

note = np.full(K + 1, -1)

note[0] = 0


def main(x):
    
    if note[x] != -1:
        
        return note[x]
        
    note[x] = 0
    
    for i in range(np.searchsorted(X, x, side='right')):
        
        note[x] += main(x - X[i])
        
        note[x] %= P
    
    return note[x]
    
print(main(K))