def can_partition_with_max_sum(arr, N, K, max_sum):
    current_sum = 0
    sections = 0
    
    for i in range(2 * N):  # we iterate through the doubled array
        current_sum += arr[i % N]
        
        if current_sum > max_sum:
            sections += 1
            current_sum = arr[i % N]
            
            if sections >= K:
                return False
    
    return True

def minimize_max_section_value(N, K, arr):
    left = max(arr)
    right = sum(arr)
    
    while left < right:
        mid = (left + right) // 2
        
        if can_partition_with_max_sum(arr, N, K, mid):
            right = mid
        else:
            left = mid + 1
            
    return left

# Read input
N, K = map(int, input().strip().split())
arr = list(map(int, input().strip().split()))

# Output the minimized maximum value of the sections
print(minimize_max_section_value(N, K, arr))