Problem:
Score : 100 points

Problem Statement

We have two integers: A and B.

Print the largest number among A + B, A - B, and A \times B.

Constraints

All values in input are integers.

-100 \leq A,\ B \leq 100

Input

Input is given from Standard Input in the following format:

A B

Output

Print the largest number among A + B, A - B, and A \times B.

Sample Input 1

-13 3

Sample Output 1

-10

The largest number among A + B = -10, A - B = -16, and A \times B = -39 is -10.

Sample Input 2

1 -33

Sample Output 2

34

The largest number among A + B = -32, A - B = 34, and A \times B = -33 is 34.

Sample Input 3

13 3

Sample Output 3

39

The largest number among A + B = 16, A - B = 10, and A \times B = 39 is 39.

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

macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        let mut next = || { iter.next().unwrap() };
        input_inner!{next, $($r)*}
    };
    ($($r:tt)*) => {
        let stdin = std::io::stdin();
        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
        let mut next = move || -> String{
            bytes
                .by_ref()
                .map(|r|r.unwrap() as char)
                .skip_while(|c|c.is_whitespace())
                .take_while(|c|!c.is_whitespace())
                .collect()
        };
        input_inner!{next, $($r)*}
    };
}

macro_rules! input_inner {
    ($next:expr) => {};
    ($next:expr, ) => {};

    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($next, $t);
        input_inner!{$next $($r)*}
    };
}

macro_rules! read_value {
    ($next:expr, ( $($t:tt),* )) => {
        ( $(read_value!($next, $t)),* )
    };

    ($next:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
    };

    ($next:expr, chars) => {
        read_value!($next, String).chars().collect::<Vec<char>>()
    };

    ($next:expr, usize1) => {
        read_value!($next, usize) - 1
    };

    ($next:expr, $t:ty) => {
        $next().parse::<$t>().expect("Parse error")
    };
}

use std::cmp::max;

fn main() {
    input! {
        a: isize,
        b: isize,
    }
    println!("{}", max(max(a + b, a * b), a - b));
}