n, k = map(int, input().split())
a = list(map(int, input().split()))
total = sum(a)

left = 1
right = total // k
answer = 0

while left <= right:
    mid = (left + right) // 2
    if total < k * mid:
        right = mid - 1
        continue
    current_sum = 0
    count = 0
    for num in a:
        current_sum += num
        if current_sum >= mid:
            count += 1
            current_sum = 0
            if count >= k:
                break
    if count >= k:
        answer = mid
        left = mid + 1
    else:
        right = mid - 1

print(answer)