## https://yukicoder.me/problems/no/2542



def main():
    L, N = map(int, input().split())
    X = list(map(int, input().split()))

    dp = [[False] * (L + 1) for _ in range(2)]
    dp[1][X[0]] = True

    prev = X[0]
    for i in range(1, N):
        new_dp = [[False] * (L + 1) for _ in range(2)]
        d = X[i] - prev
        for j in range(2):
            for t in range(L + 1):
                if dp[j][t]:
                    if t + d <= L:
                        new_dp[1][t + d] |= dp[j][t]
                    new_dp[0][t] |= dp[j][t]
        dp = new_dp
        prev = X[i]

    answer = float("inf")
    for j in range(2):
        for t in range(L + 1):
            if dp[j][t]:
                l1 = t
                l2 = L - t
                ans = abs(l2 - l1)
                answer = min(ans, answer)
    print(answer)


    








if __name__ == "__main__":
    main()