def max_min_value():
    import sys
    input = sys.stdin.read().split()
    N = int(input[0])
    K = int(input[1])
    A = list(map(int, input[2:2+N]))
    
    left = 0
    right = sum(A)
    answer = 0
    
    def is_possible(m):
        count = 0
        current_sum = 0
        for num in A:
            current_sum += num
            if current_sum >= m:
                count += 1
                current_sum = 0
                if count >= K:
                    return True
        # For circular case, check the remaining part if it can wrap around (but the code is handled as linear)
        return count >= K
    
    while left <= right:
        mid = (left + right) // 2
        if mid == 0:
            answer = mid
            left = mid + 1
            continue
        if is_possible(mid):
            answer = mid
            left = mid + 1
        else:
            right = mid - 1
    print(answer)

max_min_value()