Parallel Resistance Calculation

Given two resistors with resistances r₁ and r₂, the resistance of their parallel combination is calculated by the formula: $$R=\frac{1}{\frac{1}{r_1}+\frac{1}{r_2}}$$. Your task is to compute the resultant resistance and output the result rounded to 2 decimal places.

inputFormat

The input consists of two real numbers r₁ and r₂, separated by a space.

outputFormat

Output the value of the parallel resistance, rounded to 2 decimal places.

sample

2 3

1.20