def max_min_sum():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx])
    idx += 1
    K = int(input[idx])
    idx += 1
    A = list(map(int, input[idx:idx+N]))
    sum_A = sum(A)
    
    low = 0
    high = sum_A
    best = 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:
                    break
        return count >= K and current_sum == 0
    
    while low <= high:
        mid = (low + high) // 2
        if is_possible(mid):
            best = mid
            low = mid + 1
        else:
            high = mid - 1
    print(best)
    
max_min_sum()