K=int(input())
N=int(input())
X=list(map(int, input().split()))
mod=10**9+7

dp=[0]*(K+1)
dp[0]=1
for i in range(K):
    ok=-1
    ng=N
    while abs(ok-ng)>1:
        c=(ok+ng)//2
        if K-i>=X[c]:
            ok=c
        else:
            ng=c
    if ok==-1:
        break
    for k in range(ok+1):
        dp[i+X[k]]+=dp[i]
        dp[i+X[k]]%=mod
print(dp[-1])