pub use __cargo_equip::prelude::*;

use cplib_lang_macros::chmax;
use proconio::{fastout, input};

#[fastout]
fn main() {
    input! {
        n: usize,
        k: usize,
        a: [i64; n],
    }
    if n < k * 2 - 1 {
        println!("Impossible");
        return;
    }
    let mut dp = vec![vec![i64::MIN / 2; k + 1]; n + 1];
    dp[0][0] = 0;
    for i in 0..n {
        for j in 0..=k {
            chmax!(dp[i + 1][j], dp[i][j]);
            if j > 0 {
                chmax!(dp[i + 1][j], dp[i.saturating_sub(1)][j - 1] + a[i]);
            }
        }
    }
    let ans = dp[n][k];
    println!("{}", ans);
}

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

///  # Bundled libraries
/// 
///  - `git+https://github.com/cacampu/cplib-rs#macros@0.1.0` licensed under `MIT` as `crate::__cargo_equip::crates::cplib_lang_macros`
#[cfg_attr(any(), rustfmt::skip)]
#[allow(unused)]
mod __cargo_equip {
    pub(crate) mod crates {
        pub mod cplib_lang_macros {pub use crate::__cargo_equip::macros::cplib_lang_macros::*;#[macro_export]macro_rules!__cargo_equip_macro_def_cplib_lang_macros_chmin{($a:expr,$b:expr)=>{if$a>$b{$a=$b;true}else{false}};}macro_rules!chmin{($($tt:tt)*)=>(crate::__cargo_equip_macro_def_cplib_lang_macros_chmin!{$($tt)*})}#[macro_export]macro_rules!__cargo_equip_macro_def_cplib_lang_macros_chmax{($a:expr,$b:expr)=>{if$a<$b{$a=$b;true}else{false}};}macro_rules!chmax{($($tt:tt)*)=>(crate::__cargo_equip_macro_def_cplib_lang_macros_chmax!{$($tt)*})}#[macro_export]macro_rules!__cargo_equip_macro_def_cplib_lang_macros_mat{($e:expr;$d:expr)=>{vec![$e;$d]};($e:expr;$d:expr,$($ds:expr),+)=>{vec![mat![$e;$($ds),+];$d]};}macro_rules!mat{($($tt:tt)*)=>(crate::__cargo_equip_macro_def_cplib_lang_macros_mat!{$($tt)*})}}
    }

    pub(crate) mod macros {
        pub mod cplib_lang_macros {pub use crate::{__cargo_equip_macro_def_cplib_lang_macros_chmax as chmax,__cargo_equip_macro_def_cplib_lang_macros_chmin as chmin,__cargo_equip_macro_def_cplib_lang_macros_mat as mat};}
    }

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

    mod preludes {
        pub mod cplib_lang_macros {}
    }
}