You have ten turns to gain as many points as you can. Every turn, you can
pop two adjacent numbers **a** and **b**, gaining
**(a + b) % 10** points. As a special bonus, if you would gain
no points by doing so, you will gain a turn instead of using one up.

When you pop two numbers, they will be replaced at the site of popping by the number of points you got, and a random number will be added at the right-hand-side of the list.