Milky-Dark Chocolates

There are $N$ *milky-dark* chocolates. The $i^{th}$ chocolate has a sweetness value of $A_i$, and a bitterness value of $B_i$. Note that both values can be negative. You are going to eat all $N$ chocolates in a period of $K$ days. On the first day, you start with the first chocolate. Each subsequent day, you continue eating from where you left off the previous day, consuming a contiguous block