#region Header
#!/usr/bin/env python3
# from typing import *

import sys
import io
import math
import collections
import decimal
import itertools
from queue import PriorityQueue
import bisect
import heapq

def input():
    return sys.stdin.readline()[:-1]

sys.setrecursionlimit(1000000)
#endregion

# _INPUT = """4
# 2
# 1 3
# """
# sys.stdin = io.StringIO(_INPUT)

MOD = 1000000007

def main():
    K = int(input())
    N = int(input())
    x = list(map(int, input().split()))

    dp = [0 for _ in range(K+1)]
    dp[0] = 1
    for i in range(1, K+1):
        for j in range(N):
            if x[j] > i:
                break
            dp[i] = (dp[i] + dp[i-x[j]]) % MOD
    print(dp[K] % MOD)

if __name__ == '__main__':
    main()