from sys import stdin


def main():
    input = lambda: stdin.readline()[:-1]
    N, K = map(int, input().split())
    A = list(map(int, input().split()))

    A.sort(reverse=1)
    ans = A[0]
    for i in range(1, K):
        if A[i] > 0:
            ans += A[i]
        else:
            break
    print(ans)


main()