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)

use std::cmp::max;
use std::fs::File;
use std::io::{stdout, BufWriter, Read, Write};
use std::thread;

fn main() {
    thread::Builder::new()
        .stack_size(32 * 1024 * 1024) // 32MB
        .spawn(run)
        .unwrap()
        .join()
        .unwrap();
}

/// ローカル環境なら _in.txt から入力を受ける
fn read_input() -> String {
    let stdin = std::io::stdin();
    let mut s = String::new();
    match option_env!("LOCAL") {
        Some(_) => File::open("src/_in.txt")
            .expect("File not found")
            .read_to_string(&mut s)
            .unwrap(),
        None => stdin.lock().read_to_string(&mut s).unwrap(),
    };
    s
}

fn run() {
    let out = stdout();
    let mut out = BufWriter::new(out.lock());
    let input = read_input();
    let mut input = input.split_whitespace();

    let a: i64 = input.next().unwrap().parse().unwrap();
    let b: i64 = input.next().unwrap().parse().unwrap();

    let r1 = a * b;
    let r2 = a - b;
    let r3 = a + b;

    writeln!(out, "{}", max(r3, max(r1, r2))).ok();
}