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  1. Prepare
  2. Functional Programming
  3. Introduction
  4. Compute the Perimeter of a Polygon

Compute the Perimeter of a Polygon

You are given the cartesian coordinates of a set of points in a plane. When traversed sequentially, these points form a Polygon, , which is not self-intersecting in nature. Can you compute the perimeter of polygon ?

Input Format

The first line contains an integer, , denoting the number of points.
The subsequent lines each contain space-separated integers denoting the respective and coordinates of a point.

Constraints

  • No points are coincident, and polygon is obtained by traversing the points in a clockwise direction.

Output Format

For each test case, print the perimeter of (correct to a scale of one decimal place).

Note: Do not add any leading/trailing spaces or units.

Sample Input

4
0 0
0 1  
1 1  
1 0

Sample Output

4

Explanation

The given polygon is a square, and each of its sides are unit in length. , so we print on a new line.