Y by
In the cells of a
board, Julián writes all the integers from
to
(inclusive) in any order of his choice, without repeating numbers. For every three consecutive cells on the board, the cell containing the middle value of the three numbers in those cells is marked. For example, if the three numbers are
,
and
, then the cell with
is marked. Let
be the sum of all the numbers in the marked cells. Determine the minimum value that
can take.
Note: Each marked number contributes to the sum
exactly once, but it can be marked multiple times.









Note: Each marked number contributes to the sum
