# Home

Score : $100$ points

### Problem Statement

Assuming that the horizon seen from a place $x$ meters above the ground is $\sqrt{x(12800000+x)}$ meters away, find how many meters away the horizon seen from a place $H$ meters above the ground is.

### Constraints

• $1 \leq H \leq 10^5$
• $H$ is an integer.

### Input

Input is given from Standard Input in the following format:

$H$


### Output

Your answer will be considered correct when the absolute or relative error from the judge's answer is at most $10^{-6}$.

### Sample Input 1

333


### Sample Output 1

65287.907678222


We have $\sqrt{333(12800000+333)} = 65287.9076782\ldots$. Outputs such as 65287.91 would also be accepted.

### Sample Input 2

634


### Sample Output 2

90086.635834623


We have $\sqrt{634(12800000+634)} = 90086.6358346\ldots$.