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]
    print(ans)


if __name__ == '__main__':
    main()