A. The Fair Nut and Elevatortime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputThe Fair Nut lives in n story house. a_i people live on the i-th floor of the house. Every person uses elevator twice a day: to get from the floor where he/she lives to the ground (first) floor and to get from the first floor to the floor where he/she lives, when he/she comes back home in the evening. It was decided that elevator, when it is not used, will stay on the x-th floor, but x hasn't been chosen yet. When a person needs to get from floor a to floor b, elevator follows the simple algorithm:   Moves from the x-th floor (initially it stays on the x-th floor) to the a-th and takes the passenger.  Moves from the a-th floor to the b-th floor and lets out the passenger (if a equals b, elevator just opens and closes the doors, but still comes to the floor from the x-th floor).  Moves from the b-th floor back to the x-th.  The elevator never transposes more than one person and always goes back to the floor x before transposing a next passenger. The elevator spends one unit of electricity to move between neighboring floors. So moving from the a-th floor to the b-th floor requires |a - b| units of electricity.Your task is to help Nut to find the minimum number of electricity units, that it would be enough for one day, by choosing an optimal the x-th floor. Don't forget than elevator initially stays on the x-th floor. InputThe first line contains one integer n (1 \leq n \leq 100) — the number of floors.The second line contains n integers a_1, a_2, \ldots, a_n (0 \leq a_i \leq 100) — the number of people on each floor.OutputIn a single line, print the answer to the problem — the minimum number of electricity units.ExamplesInput30 2 1Output16Input21 1Output4NoteIn the first example, the answer can be achieved by choosing the second floor as the x-th floor. Each person from the second floor (there are two of them) would spend 4 units of electricity per day (2 to get down and 2 to get up), and one person from the third would spend 8 units of electricity per day (4 to get down and 4 to get up). 4 \cdot 2 + 8 \cdot 1 = 16.In the second example, the answer can be achieved by choosing the first floor as the x-th floor.
Input30 2 1
Output16
['brute force', 'implementation', '*1000']