Fence Colouring

You have $N$ fences, and you want to colour them. You have $N$ total types of colours numbered $1, 2, \ldots, N$. Currently, all the $N$ fences are coloured with the type $1$ colour. At the end, you want the $i$-th fence to have a colour of $A_i$ for every $1 \le i \le N$. You can choose to do one of the following at each minute: - Colour all $N$ fences at the same time with type $X$ colour, wh