#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
int total[100][100];
int a[100][100];
int f[100][100][800];
int ans,n,m;
int main(){
	freopen("brike.in","r",stdin);
	freopen("brike.out","w",stdout);
    memset(f,-1,sizeof(f));
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;++i){
        for(int j=1;j<=n-i+1;++j){
            scanf("%d",&a[n-j+1][i]);
        }
    }
    for(int i=1;i<=n;++i){
        for(int j=1;j<=i;++j){
            total[i][j]=total[i][j-1]+a[i][j];
        }
    }
    for(int i=0;i<=n;++i){
        f[i][0][0]=0;
    }
    f[1][1][1]=a[1][1];
    for(int i=2;i<=n;++i){
        for(int j=0;j<=i;++j){
            for(int k=0;k<=m;++k){
                if(k>=j){
                    for(int p=j-1;p<=i-1;++p){
                        if(f[i-1][p][k-j]>-1){
                            if(f[i][j][k]<total[i][j]+f[i-1][p][k-j]){
                                f[i][j][k]=total[i][j]+f[i-1][p][k-j];
                                ans=max(ans,f[i][j][k]);
                            }
                        }
                    }   
                }
            }
        }
    }
    printf("%d",ans);
    fclose(stdin);
    fclose(stdout);
    return 0;
}