A13589 | Uncle Bogdan and Projections

After returning to shore, uncle Bogdan usually visits the computer club "The Rock", to solve tasks in a pleasant company. One day, uncle Bogdan met his good old friend who told him one unusual task...

There are $n$ non-intersecting horizontal segments with ends in integers points on the plane with the standard cartesian coordinate system. All segments are strictly above the $OX$ axis. You can choose an arbitrary vector ( $a$ , $b$ ), where $b < 0$ and coordinates are real numbers, and project all segments to $OX$ axis along this vector. The projections shouldn't intersect but may touch each other.

Find the minimum possible difference between $x$ coordinate of the right end of the rightmost projection and $x$ coordinate of the left end of the leftmost projection.

The first line contains the single integer $n$ ( $1 \le n \le 2000$ ) — the number of segments.

The $i$ -th of the next $n$ lines contains three integers $xl_i$ , $xr_i$ and $y_i$ ( $-10^6 \le xl_i < xr_i \le 10^6$ ; $1 \le y_i \le 10^6$ ) — coordinates of the corresponding segment.

It's guaranteed that the segments don't intersect or touch.

Print the minimum possible difference you can get.

Your answer will be considered correct if its absolute or relative error doesn't exceed $10^{-6}$ .

Formally, if your answer is $a$ and jury's answer is $b$ then your answer will be considered correct if $\frac{|a - b|}{\max{(1, |b|)}} \le 10^{-6}$ .