Problems

# The surface area of the cone

Calculate the total surface area of a truncated cone, if we know the base radius R, r and height h.

Input

In a single line of succession through a gap defined, respectively, the base radius R, r and height h. All input data are integers, not exceeding 100.

Output

In a single line to bring the total surface area of a truncated cone. Result output to two decimal places.

Time limit 1 second
Memory limit 64 MiB
Input example #1
4 3 5

Output example #1
190.67