from collections import deque

def solution(N, K, durabilities):
    belt = deque(durabilities)
    robots = deque([False] * N)

    step = 0

    while True:
        step += 1


        belt.rotate(1)
        robots.rotate(1)
        robots[-1] = False


        for i in range(N - 2, -1, -1):
            if robots[i] and not robots[i + 1] and belt[i + 1] > 0:
                robots[i] = False
                robots[i + 1] = True
                belt[i + 1] -= 1

        robots[-1] = False


        if belt[0] > 0:
            robots[0] = True
            belt[0] -= 1


        if belt.count(0) >= K:
            return step


N = 3
K = 2
durabilities = [1, 2, 1, 2, 1, 2]

print(solution(N, K, durabilities))