n, k = [int(i) for i in input().split()]
players = [int(i) for i in input().split()]

players_top = list(enumerate(players))

best = (0, -1000000000000)

end = -k + 1
if end == 0:
    end = n + 1

for player in sorted(players_top, key=lambda x:x[0])[k - 1: end]:
    value = player[1] - max([9999999] if len(players[player[0] + 1:]) == 0 else players[player[0] + 1:])
    best_id, best_value = best

    if value > best_value:
        best = player

left = sorted(players[:best[0] + 1])[::-1]
right = sorted(players[best[0] + 1:])

print(sum(left[:k]) - sum(right[:k]))