There are 100 lightbulbs B_{1}, \ldots, B_{100} spaced evenly around a circle in this order. Additionally, there are 100 switches S_{1}, \ldots, S_{100} such that for all 1 \leq i \leq 100, switch S_{i} toggles the states of lights B_{i-1} and B_{i+1} (where here B_{101}=B_{1}). Suppose David chooses whether to flick each switch with probability \frac{1}{2}. What is the expected number of lightbulbs which are on at the end of this process given that not all lightbulbs are off?