# Problem: Areas of Figures

Write a program that inputs the sizes of a geometric figure and calculates its area. The figures are four types: square, rectangle, circle and triangle.

The first line of the input provides the type of the figure (square, rectangle, circle, triangle).

• If the figure is a square, the next line provides one number – the length of its side.
• If the figure is a rectangle, the next two lines we provide two numbers – the lengths of its sides.
• If the figure is a circle, the next line provides one number – the radius of the circle.
• If the figure is a triangle, the next two lines provide two numbers – the length of the side and the length of its height.

Round the result up to the third digit after the decimal point.

Input Output
square
5
25
rectangle
7
2.5
17.5
circle
6
113.097
triangle
4.5
20
45