pub use __cargo_equip::prelude::*;

use macros::{chmax, chmin};
#[allow(unused_imports)]
use proconio::{
    fastout, input,
    marker::{Bytes, Chars, Usize1},
};

const INF: i64 = 1 << 60;

#[fastout]
fn main() {
    input! {
        n: usize,
        mut a: [i64; n],
    }
    let calc = |a: &[i64]| {
        let mut min = vec![INF; n + 1];
        let mut max = vec![-INF; n + 1];
        for i in 0..n {
            chmin!(min[i + 1], 0.min(min[i]) + a[i]);
            chmax!(max[i + 1], 0.max(max[i]) + a[i]);
        }
        for i in 1..n - 1 {
            chmin!(min[i + 1], min[i]);
            chmax!(max[i + 1], max[i]);
        }
        (min, max)
    };
    let (f0, f1) = calc(&a);
    a.reverse();
    let (mut f2, mut f3) = calc(&a);
    f2.reverse();
    f3.reverse();
    let mut res = -INF;
    for i in 1..n {
        chmax!(res, f0[i] * f2[i]);
        chmax!(res, f0[i] * f3[i]);
        chmax!(res, f1[i] * f2[i]);
        chmax!(res, f1[i] * f3[i]);
    }
    println!("{}", res);
}

// The following code was expanded by `cargo-equip`.

///  # Bundled libraries
/// 
///  - `path+file:///comp_rust/cprs/crates/misc/macros#0.1.0` published in **missing** licensed under `CC0-1.0` as `crate::__cargo_equip::crates::macros`
#[cfg_attr(any(), rustfmt::skip)]
#[allow(unused)]
mod __cargo_equip {
    pub(crate) mod crates {
        pub mod macros {pub use crate::__cargo_equip::macros::macros::*;mod chminmax{#[macro_export]macro_rules!__cargo_equip_macro_def_macros_min{($a:expr$(,)*)=>{{$a}};($a:expr,$b:expr$(,)*)=>{{std::cmp::min($a,$b)}};($a:expr,$($rest:expr),+$(,)*)=>{{std::cmp::min($a,$crate::__cargo_equip::crates::macros::min!($($rest),+))}};}macro_rules!min{($($tt:tt)*)=>(crate::__cargo_equip_macro_def_macros_min!{$($tt)*})}#[macro_export]macro_rules!__cargo_equip_macro_def_macros_max{($a:expr$(,)*)=>{{$a}};($a:expr,$b:expr$(,)*)=>{{std::cmp::max($a,$b)}};($a:expr,$($rest:expr),+$(,)*)=>{{std::cmp::max($a,$crate::__cargo_equip::crates::macros::max!($($rest),+))}};}macro_rules!max{($($tt:tt)*)=>(crate::__cargo_equip_macro_def_macros_max!{$($tt)*})}#[macro_export]macro_rules!__cargo_equip_macro_def_macros_chmin{($base:expr,$($cmps:expr),+$(,)*)=>{{let cmp_min=$crate::__cargo_equip::crates::macros::min!($($cmps),+);if$base>cmp_min{$base=cmp_min;true}else{false}}};}macro_rules!chmin{($($tt:tt)*)=>(crate::__cargo_equip_macro_def_macros_chmin!{$($tt)*})}#[macro_export]macro_rules!__cargo_equip_macro_def_macros_chmax{($base:expr,$($cmps:expr),+$(,)*)=>{{let cmp_max=$crate::__cargo_equip::crates::macros::max!($($cmps),+);if$base<cmp_max{$base=cmp_max;true}else{false}}};}macro_rules!chmax{($($tt:tt)*)=>(crate::__cargo_equip_macro_def_macros_chmax!{$($tt)*})}}#[allow(unused_imports)]pub use chminmax::*;mod mvec{#[macro_export]macro_rules!__cargo_equip_macro_def_macros_mvec{($x:expr;$n:expr)=>{vec![$x;$n]};($x:expr;$n:expr$(;$m:expr)+)=>{vec![mvec![$x$(;$m)*];$n]};}macro_rules!mvec{($($tt:tt)*)=>(crate::__cargo_equip_macro_def_macros_mvec!{$($tt)*})}}#[allow(unused_imports)]pub use mvec::*;mod yes{#[macro_export]macro_rules!__cargo_equip_macro_def_macros_yes{()=>{{println!("Yes");}};($a:expr)=>{{if$a{println!("Yes");}else{println!("No");}}};}macro_rules!yes{($($tt:tt)*)=>(crate::__cargo_equip_macro_def_macros_yes!{$($tt)*})}}#[allow(unused_imports)]pub use yes::*;}
    }

    pub(crate) mod macros {
        pub mod macros {pub use crate::{__cargo_equip_macro_def_macros_chmax as chmax,__cargo_equip_macro_def_macros_chmin as chmin,__cargo_equip_macro_def_macros_max as max,__cargo_equip_macro_def_macros_min as min,__cargo_equip_macro_def_macros_mvec as mvec,__cargo_equip_macro_def_macros_yes as yes};}
    }

    pub(crate) mod prelude {pub use crate::__cargo_equip::crates::*;}

    mod preludes {
        pub mod macros {}
    }
}