Problem - Police Chase

You are given a city map with $n$ intersections and $m$ roads. Each road is bidirectional. The police want to block some roads to prevent criminals from reaching intersection $n$ from intersection $1$. What is the minimum number of roads they need to block?

Output that number and list the roads to block. This is a minimum $s$-$t$ cut problem where $s = 1$ and $t = n$. Each road has capacity $1$. You are finding the smallest set of roads whose removal disconnects the source from the destination.