Description

Given $f(x,n)=\sqrt{n+\sqrt{(n-1)+\sqrt{(n-2)+\sqrt{...+2+\sqrt{1+x}}}}}$, calculate the value of $f$ when $x=4.2$, $n=10$ and $x=2.5$, $n=15$.

Input Format

Input $x$ and $n$.

Output Format

The function value, rounded to two decimal places.

4.2 10

3.68