def main():
    import sys
    input = sys.stdin.read
    data = input().split()
    
    N = int(data[0])
    K = int(data[1])
    A = list(map(int, data[2:2+N]))
    
    total_sum = sum(A)
    low = 0
    high = total_sum
    ans = 0

    def can_split(mid):
        if mid == 0:
            return True
        if total_sum < mid * K:
            return False
        for i in range(N):
            current_sum = 0
            cnt = 0
            for j in range(N):
                pos = (i + j) % N
                current_sum += A[pos]
                if current_sum >= mid:
                    cnt += 1
                    current_sum = 0
                    if cnt >= K:
                        return True
        return False

    while low <= high:
        mid = (low + high) // 2
        if can_split(mid):
            ans = mid
            low = mid + 1
        else:
            high = mid - 1
    print(ans)

if __name__ == '__main__':
    main()