961-22 guruh, Musobaqa#1

Problem Tasks

# Date State
Not Contest

# Date State

D. Yakuniy_1_J

Time limit : 1000 ms
Memory limit : 64 mb

Berilgan yig’indini hisoblang:


$$S = \frac{log_xy}{2 ^ 1} + \frac{log_xy^3}{2^2} + ... + \frac{log_xy^{2n-1}}{2^n}$$


Kiruvchi ma’lumotlar: Birinchi satrda uchta $n$ $(1 \le n \le 10)$, $x$$(2 \le x \le 10)$ va $y$(1 \le y \le 10)$ butun sonlar berilgan.


Chiquvchi ma’lumotlar: Yagona $S$ haqiqiy sonni chop qiling. Natija $10^{-2}$ aniqlikda chiqarilsin.

Input
2 3 4
Output
1.58
Input
2 6 2
Output

0.48