use proconio::input;
use std::cmp::max;

fn main(){
    input!{
        n: usize,
        k: usize,
        a: [i64; n],
    }

    if n < 2*k{
        println!("Impossible");
        return;
    }

    let mut dp = vec![vec![vec![i64::MIN/128; 2]; k+1]; n+1];
    dp[0][0][0] = 0;
    for i in 0..n{
        for j in 0..=k{
            for l in 0..2{
                if l == 0 && j < k{
                    dp[i+1][j+1][1] = dp[i+1][j+1][l].max(dp[i][j][l]+a[i]);
                }
                dp[i+1][j][0] = dp[i+1][j][0].max(dp[i][j][l]);
            }
        }
    }

    println!("{}", max(dp[n][k][0], dp[n][k][1]));
}