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

low = 0
high = total // k
ans = 0

while low <= high:
    mid = (low + high) // 2
    current = 0
    count = 0
    for num in a:
        current += num
        if current >= mid:
            count += 1
            current = 0
    if count >= k:
        ans = mid
        low = mid + 1
    else:
        high = mid - 1

print(ans)