mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    N, K = map(int, input().split())
    A = list(map(int, input().split()))
    A.sort(reverse=True)
    ans = 0
    for k in range(K):
        if A[k] > 0:
            ans += A[k]
    if ans != 0:
        print(ans)
    else:
        print(A[0])


if __name__ == '__main__':
    main()