Problem Statement

On the $xy$-plane, we have a passage surrounded by the two lines $y=-100$ and $y=100$.

In the part of this passage with $-100 < x < 100$, there are $N$ negligibly small nails. The coordinates of the $i$-th nail are $(x_i, y_i)$.

Takahashi will choose a real number $r \ (0 < r \leq 100)$ and put a circle of radius $r$ so that its center is at $(-10^9, 0)$.

Then, he will move the circle from $(-10^9, 0)$ to $(10^9, 0)$.

Here, he continuously moves the circle so that the boundaries of the passage or the nails do not penetrate the interior of the circle.

Find the maximum possible value of $r$ such that it is possible to move the circle to $(10^9, 0)$.

Constraints

• All values in input are integers.
• $1 \leq N \leq 100$
• $|x_i|, |y_i| < 100$
• If $i \neq j$, $(x_i, y_i) \neq (x_j, y_j)$.

Input

Input is given from Standard Input in the following format:

N
x_1 y_1
\vdots
x_N y_N

Output

Print the maximum possible value of $r$ such that it is possible to move the circle to $(10^9, 0)$. Your output will be considered correct when its absolute or relative error from our answer is at most $10^{-4}$.