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#include <bits/stdc++.h>

using namespace std;
#define PII pair<int,int>

long long a[205];
long long dp[205][205][70];
long long pref[205];
long long DP[205][70];
long long M[70];

int main()
{
    ios_base::sync_with_stdio(0);
    int n;
    long long m;
    cin>>n>>m;
    m++;
    for(int i=1;i<=n;i++)cin>>a[i];
    for(int i=1;i<=n;i++)pref[i]=pref[i-1]+a[i];

    for(int k=1;k<=65;k++)
    {
        for(int d=0;d<n;d++)
        {
            for(int x=1;x<=n-d;x++)
            {
                dp[x][x+d][k]=-2*1e18;
                if((long long)d+1>((long long)1<<k))continue;
                if((long long)d+1<=((long long)1<<(k-1)))dp[x][x+d][k]=max(dp[x][x+d][k-1],dp[x][x+d][k-1]+pref[x+d]-pref[x-1]);
                for(int i=x-1;i<=x+d;i++)
                {
                    if((long long)i-x+1>((long long)1<<(k-1))||(long long)x+d-i>((long long)1<<(k-1)))continue;
                    dp[x][x+d][k]=max(dp[x][x+d][k],dp[x][i][k-1]+dp[i+1][x+d][k-1]+pref[x+d]-pref[i]);
                }
            }
        }
    }

  /*  for(int k=0;k<3;k++)
    {
        cout<<k<<endl;
        for(int i=0;i<=n;i++)
        {
            for(int j=0;j<=n;j++)cout<<dp[i][j][k]<<" ";
            cout<<endl;
        }cout<<endl;
    }*/

    int cnt=0;
 //   long long M=0;
    for(int k=60;k>=0;k--)
    {
		M[k]=M[k+1];
        if((m&((long long)1<<k))!=0)
        {
            M[k]+=((long long)1<<k);
            for(int i=1;i<=n;i++)
            {
                DP[i][k]=-2*1e18;
                if((long long)i>M[k])continue;
                if((long long)i<=M[k+1])DP[i][k]=max(DP[i][k],DP[i][k+1]);
     //           if((long long)i<=((long long)1<<k))DP[i][k]=max(DP[i][k],dp[1][i])
                for(int j=0;j<=i;j++)
                {
                    if((long long)i-j>((long long)1<<k)||(long long)j>M[k+1])continue;
                    DP[i][k]=max(DP[i][k],DP[j][k+1]+dp[j+1][i][k]+cnt*(pref[i]-pref[j]));
                }
            }
            cnt++;
        }
        else for(int i=1;i<=n;i++)DP[i][k]=DP[i][k+1];

    /*    if(k<3)
        {
            cout<<k<<" "<<cnt<<endl;
            for(int i=0;i<=n;i++)cout<<DP[i][k]<<" ";
            cout<<endl<<endl;
        }*/
    }
    cout<<DP[n][0]<<endl;
}