###### Category

###### Similar Problems

## 0737. Goat in the garden_2

###### Time limit : 1000 ms

Memory limit : 64 mb

# Someone has let a goat in a square kitchen-garden and had bound it to a stake. The stake is driven into the ground in the very midst of the square. The goat is hungry as a hunter and very voracious, and eats everything that can be reached without leaving the square and tearing off the rope. What area of the kitchen-garden will be ate round?

**Input**

Contains
lengths of the garden sides and a cord length in meters (positive integers not
exceeding **1000**, located in one line and separated with a
space).

**Output **

Should
contain an area of the kitchen-garden (in square meters to within **6** symbols after a decimal point), ate
round by the goat.

Samples

№ |
Input |
Output |

1 |
10 6 |
95.091113 |

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