You are now in a supermarket and notice that a promotion is being held. The promotional device consists of

lights arranged in

rows, with two lights in each row.
Each time, you press the button for every row. For the

-th row:
-
If light
is on, you gain
points.
-
If light
is on, you gain
points.
Each row has an associated probability

, where:
-
Light
is on with probability
.
-
Light
is on with probability
.
For one round of the event, your total score is defined as the
product of the points obtained from all rows.
There is also a
random button. After pressing it,

rows are chosen at random. In each of those selected rows, the two lights are swapped (that is, if light

is on, you gain

points; if light

is on, you gain

points).
You want to determine whether pressing this random button can improve your expected points. Therefore, you decide to compute the expected value of your final points after pressing the random button modulo

.