import sys

def main():
    N, K = map(int, sys.stdin.readline().split())
    A = list(map(int, sys.stdin.readline().split()))
    if K == 0:
        print(0)
        return
    total = sum(A)
    if K == 1:
        print(total)
        return
    low = 0
    high = total
    best = 0
    B = A + A
    while low <= high:
        mid = (low + high) // 2
        if mid == 0:
            best = max(best, 0)
            low = mid + 1
            continue
        if total < K * mid:
            high = mid - 1
            continue
        found = False
        for i in range(N):
            current = 0
            count = 0
            j = i
            while j < i + N:
                current += B[j]
                if current >= mid:
                    count += 1
                    current = 0
                    if count >= K:
                        break
                j += 1
            if count >= K:
                found = True
                break
        if found:
            best = mid
            low = mid + 1
        else:
            high = mid - 1
    print(best)

if __name__ == "__main__":
    main()