H1

#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include <cmath>

using namespace std;

int main()
{
    long long n, k;
    cin >> n >> k;
    vector<long long> a(n + 1);
    vector<vector<long long>> dp(k + 1, vector<long long>(n + 1, 1e9));
    dp[0][0] = 0;
    for (int i = 1; i <= n; ++i)
    {
        cin >> a[i];
    }
    if (k < n || n + 1 < k)
    {
        cout << "Impossible";
        return 0;
    }
    for (int i = 1; i <= k; ++i)
    {
        for (int j = 1; j <= n; ++j)
        {
            for (int q = 0; q < n; ++q)
            {
                if (i >= q + 1 && j >= q)
                {
                    dp[i][j] = max(dp[i][j], max(dp[i - q][j - q] + a[q + 1], dp[i - q - 1][i - q] + a[q + 1]));
                }
                else if (i >= q && j >= q)
                {
                    dp[i][j] = max(dp[i][j], dp[i - q][j - q] + a[q]);
                }
            }
        }
    }
    long long ans = -1;
    for (int i = 0; i < n; ++i)
    {
        for (int j = 0; j < n; ++j)
        {
            if (k - i == n - j || k - i + 1 == n - j)
            {
                if (dp[i][j] < 1e9)
                {
                    ans = max(ans, dp[i][j]);
                }
            }
        }
    }
    cout << ans ;
    return 0;
}