Right-Angled Triangle Area Calculator

You are given the three side lengths of a triangle. Your task is to determine whether the triangle is a right-angled triangle. A triangle is right-angled if, after sorting its side lengths in non-decreasing order as \(a \leq b \leq c\), the Pythagorean theorem holds: \(a^2 + b^2 = c^2\).

If the triangle is right-angled, compute and output the area of the triangle using the formula \(\text{area} = \frac{1}{2}ab\). Otherwise, output the exact string "Not a right-angled triangle".

Note: The input will consist of three numbers separated by spaces in a single line. The output should be printed to stdout.

inputFormat

The input consists of a single line containing three space-separated numbers \(a\), \(b\), and \(c\) representing the lengths of the sides of the triangle.

outputFormat

If the triangle is right-angled, print its area as a floating-point number with one decimal place. Otherwise, print "Not a right-angled triangle".

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