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

def is_possible(x):
    if total < x * k:
        return False
    current_sum = 0
    count = 0
    for num in a:
        current_sum += num
        if current_sum >= x:
            count += 1
            current_sum = 0
            if count >= k:
                return True
    return False

low = 0
high = total // k
answer = 0

while low <= high:
    mid = (low + high) // 2
    if is_possible(mid):
        answer = mid
        low = mid + 1
    else:
        high = mid - 1

print(answer)