Cake#112
At a birthday party, a huge festive cake was served to three friends. The first friend could eat the entire cake by themselves in t_1 hours, the second in t_2 hours, and the third in t_3 hours.
How much time will it take the three friends to eat the whole cake together?
The only line contains three non-negative integers t_1, t_2, and t_3, each not exceeding .
Print the time in hours it takes for the three friends to eat the cake together. Round the result to two decimal places.
Example 1