26396번 - Neboderi 서브태스크다국어

Domagoj is in the big city of London! Right now, there is a sequence of tall skyscrapers in front of him and he wants to take a photograph to remember the moment.

The sequence of skyscrapers can be represented as a sequence of n numbers h₁, h₂, . . . , h_n where the number hi represents the height of the i-th skyscraper. Domagoj will photograph a contiguous subsequence of skyscrapers. To capture more of the city’s beauty, he wants to photograph at least k skyscrapers.

Domagoj has a strange sense of beauty of a photograph. He is very happy when there are tall skyscrapers in the photograph, but he is even happier when their heights have a large common divisor! If we label the heights of the contiguous skyscrapers on the photograph with h_l, . . . , h_r, and with g the greatest common divisor of the selected heights, then Domagoj defines the beauty of the photograph as g · (h_l + . . . + h_r).

Help Domagoj determine the beauty of the most beautiful photograph with at least k skyscrapers!

The first line contains two integers n, k (1 ≤ k ≤ n ≤ 10⁶), the number of skyscrapers, and the number k.

The second line contains n integers h₁, h₂, . . . , h_n (1 ≤ h_i ≤ 10⁶), the heights of the skyscrapers, in order.

Print a single line with the required number from the task.

Clarification of the first example: Domagoj photographed skyscrapers ( 4, 4, 4 ), so the total beauty is 4 · (4 + 4 + 4) = 48

Clarification of the second example: Domagoj photographed only the skyscraper ( 9 ), so the total beauty is 9 · 9 = 81.