K = int(input())

N = int(input())

import numpy as np


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

import sys

sys.setrecursionlimit(10 ** 9)

P = 10 ** 9 + 7

note = np.full(K + 1, -1)
note[0] = 1

def main(x):
    if x < 0:
        
        return 0
    
    if note[x] != -1:
        
        return note[x]
    
    note[x] = 0
    
    for i in X:
        
        if i > x:
            break
        
        note[x] += main(x - i)
        
        note[x] %= P
    
    return note[x]
    
print(main(K))