#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int n,c[55][55],m,u;
int f[55][550][55];
int main()
{
	freopen("brike.in","r",stdin);
	freopen("brike.out","w",stdout);
	scanf("%d%d",&n,&m);
	for(int y=1;y<=n;y++)
		for(int i=y;i<=n;i++)
		{
			int h;
			scanf("%d",&h);
			c[i][y]=c[i][y-1]+h;
		}
	for(int i=1;i<=n;i++)// i is the line
		for(int k=0;k<=i;k++)//in this line,k wood were killed
			for(int j=0;j<=min(m,(1+i)*i/2);j++)// j is the number of the wood killed
				if(k<=j)
				for(int p=max(k-1,0);p<=i-1;p++)
					if(j>=p+k)
						if(f[i][j][k]<f[i-1][j-k][p]+c[i][k])
						{
							f[i][j][k]=f[i-1][j-k][p]+c[i][k];
							/*if(f[i][j][k]==64)
								printf("%d %d %d\n",i,j,k);*/
							if(j==m&&f[i][j][k]>u)
								u=f[i][j][k];
						}
	printf("%d",u);
}