C PROGRAMING! Calculate the perimeter of a polygon with n vertex coordinates input clockwise by the keyboard. The coordinates of each vertex are expressed in structure, and the n value does not exceed 10. [Input] enter an integer as the value of n;

two double numbers in each row are the coordinates of vertices of the polygon. [Output] The perimeter of the polygon, accurate to 2 decimal places. [Example of input]

4 0 0 0 1 1 1 1 0

[Output example] 4.00