ABC Company has just installed a new production line. The company is considering the appropriate method and rate of depreciation for each year. By design, the equipment has a shelf life of ~N~ years. In the first year, the depreciation rate is assumed to be ~X~, the company wants the depreciation rate to decrease gradually according to the number of years of use as follows:

• First year: ~X~
• Second year ~X – X*1/N~
• Third year: ~X – X*2/N~
• …

After ~N~ years of usages, the value of the equiqment is ~R~. Caculate the initial value of ~X~

Input

• A single line has three numbers separated by a space, the corresponding number of years using ~N~ (~1 \leq N \leq 1000~), initial value ~C~ (~0 < C < 10^{18}~), and residual value (~0 < R < 10^{18}~) .

Output

• Print out the depreciation rates for the first year with ~6~ decimal place accuracy

Example Input 1

5 1000000000 500000000

Example Output 1

0.2122959