#include <cstdlib>
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <map>
#include <stack>
#include <queue>
#include <ctime>
#include <algorithm>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef unsigned int uint;
const int inf=1061109567;
const int maxn=55;
const int maxm=510;
const int mod=7777777;

int f[maxn][maxm][maxm];
int s[maxn][maxn];

int main()
{
    freopen("brike.in","r",stdin);
    freopen("brike.out","w",stdout);
    //clock_t st=clock();
    int n,m,a;scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n-i+1;j++)
        {
            scanf("%d",&a);
            s[i+j-1][i]=s[i+j-1][i-1]+a;
        }
    }
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=m;j++)
        {
            for(int k=1;k<=j;k++)
            {
                for(int p=k-1;p<=j-k;p++)
                {
                    f[i][j][k]=max(f[i][j][k],f[i-1][j-k][p]+s[i][k]);
                }
            }
        }
    }
    int ans=0;
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=i;j++)
        {
            ans=max(ans,f[i][m][j]);
        }
    }
    printf("%d\n",ans);
    //clock_t ed=clock();
    //printf("\nTime used : %.5lf Ms\n",double(ed-st)/CLOCKS_PER_SEC);
    return 0;
}