import sys

def main():
    N, K = map(int, sys.stdin.readline().split())
    A = list(map(int, sys.stdin.readline().split()))
    total = sum(A)
    if K == 0:
        print(0)
        return
    left = 1
    right = total // K
    answer = 0

    while left <= right:
        mid = (left + right) // 2
        current_sum = 0
        count = 0
        for a in A:
            current_sum += a
            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)

if __name__ == '__main__':
    main()