Bees and Flowers

Bees collect pollen and nectar from a variety of flowers. There are $N$ bees and $N$ flowers, placed in a straight line. Each flower can only be used by one bee. In an operation, a bee can either stay in it's position or move to it's left from $x$ to it's $x - 1$ or move to right from $x$ to $x + 1$. Each operation consumes $1$ unit time. All the bees start at the same time and can move simultane