Goat Rope

문제

You have a fence post located at the point (x, y) in the plane, to which a goat is tethered by a rope. You also have a house, which you model as an axis-aligned rectangle with diagonally opposite corners at the points (x₁, y₁) and (x₂, y₂). You want to pick a length of rope that guarantees the goat cannot reach the house. Determine the minimum distance from the fence post to the house, so that you can make sure to use a shorter rope.

입력

The input consists of a single line containing six space-separated integers x, y, x₁, y₁, x₂, and y₂, each in the range [−999, 999].

It is guaranteed that x₁ < x₂ and y₁ < y₂, and that (x, y) is strictly outside the axis-aligned rectangle with corners at (x₁, y₁) and (x₂, y₂).

출력

Print the minimum distance from the goat’s post to the house, with a relative or absolute error no more than 0.001.