#include <iostream>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <cmath>

using namespace std;

int a[51][51],n,m;
int s[51][51];
int f[51][51][501];
bool y[51][51][501];
int dp(int u,int b,int l)
{
	if (u>n || l<=0) return 0;
	if (y[u][b][l]) return f[u][b][l];
	y[u][b][l]=true;
	int t=min(b,l);
	for (int i=0;i<=t;i++)
		f[u][b][l]=max(f[u][b][l],s[u][i]+dp(u+1,i+1,l-i));
	return f[u][b][l];
}

int main()
{
	freopen("skill.in","r",stdin);
	freopen("skill.out","w",stdout);
	scanf("%d%d",&n,&m);
	for (int i=1;i<=n;i++)
	for (int j=i;j<=n;j++)
	scanf("%d",&a[j][i]);
	for (int i=1;i<=n;i++)
	for (int j=1;j<=i;j++)
	s[i][j]=s[i][j-1]+a[i][j];
	printf("%d\n",dp(1,1,m));
	return 0;
}