Description

lmh is now doing a math problem, known to have the coordinates of $n$ points, find the shortest distance to connect the $n$ points, can you give him some advice?

Format

Input

Input contains multiple test cases. The first line contains $0 < n \leq 1000$, the number of point. For each point, a line follows; each following line contains two real numbers indicating the $(x,y)$ coordinates of the point.

Output

The shortest distance.prints a single real number to two decimal places.

Samples

3
1.0 1.0
2.0 2.0
2.0 4.0

3.41