use std::arch::x86_64::_mm_packus_epi16;


fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let mut a = String::new();
    std::io::stdin().read_line(&mut a).ok();
    let a: Vec<isize> = a.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();

    let mut cands = vec![a[0], a[0]];
    for i in 1..n {
        let mut ncands = vec![];
        for &v in cands.iter() {
            ncands.push(v + a[i]);
            ncands.push(v - a[i]);
            ncands.push(v * a[i]);
            ncands.push(v / a[i]);
        }
        ncands.sort();
        cands = vec![ncands[0], ncands[ncands.len()-1]];
    }
    println!("{}", cands[1]);
}