import bisect

MOD = 10**9 + 7

def main():
    import sys
    input = sys.stdin.read().split()
    ptr = 0
    K = int(input[ptr])
    ptr +=1
    N = int(input[ptr])
    ptr +=1
    x = list(map(int, input[ptr:ptr+N]))
    ptr +=N
    x.sort()
    
    dp = [0]*(K+1)
    dp[0] = 1
    
    for i in range(1, K+1):
        # 找到最大的x_j <=i
        idx = bisect.bisect_right(x, i) - 1
        # 遍历所有x_j <=i
        for j in range(idx+1):
            xj = x[j]
            if xj > i:
                break
            dp[i] += dp[i - xj]
            dp[i] %= MOD
    print(dp[K] % MOD)

if __name__ == "__main__":
    main()