Problem:
Score : 100 points

Problem Statement

Given is an integer r.

How many times is the area of a circle of radius r larger than the area of a circle of radius 1?

It can be proved that the answer is always an integer under the constraints given.

Constraints

1 \leq r \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

r

Output

Print the area of a circle of radius r, divided by the area of a circle of radius 1, as an integer.

Sample Input 1

2

Sample Output 1

4

The area of a circle of radius 2 is 4 times larger than the area of a circle of radius 1.

Note that output must be an integer - for example, 4.0 will not be accepted.

Sample Input 2

100

Sample Output 2

10000

Solution in Rust (1.15.1) (judge verdict: Accepted)

use std::io::Read;

pub fn read_stdin() -> String {
    let mut s = String::new();
    ::std::io::stdin().read_to_string(&mut s).unwrap();
    s
}

pub trait Parse {
    fn to<T>(&mut self) -> T
    where
        T: std::str::FromStr;
}

impl<'a> Parse for std::str::SplitWhitespace<'a> {
    fn to<T>(&mut self) -> T
    where
        T: std::str::FromStr,
    {
        let word = self.next().unwrap();
        word.parse().ok().unwrap()
    }
}

fn main() {
    let source = read_stdin();
    let mut iter = source.split_whitespace();
    let r: u32 = iter.to();
    println!("{}", r * r);
}