Chile

In a particularly large country, there are $N$ cities connected by some bidirectional public roads. The public road network can be represented as a binary string $\overline{a_1a_2\ldots a_{N-1}}$, where: - $a_i=1$, if there is a bidirectional road between cities $i$ and $i+1$. - $a_i=0$, otherwise. However, this network sometimes isn't enough, and more roads need to be built. There are $Q$ diffe