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.