502

#include <bits/stdc++.h>

using namespace std;

//constants

const int MAXN=(int)(1e6+1e1);

const double PI=acos(-1.0);

//defines

#define ll long long

#define fr freopen("input.txt","r",stdin);

#define fw freopen("output.txt","w",stdout);

#define mp make_pair

#define pb push_back

#define eof (-1)

#define forr(xx,yy,zz) for(int zz=xx;zz<=yy;zz++)

#define forl(xx,yy,zz) for(int zz=xx;zz>=yy;zz--)

#define sqr(x) ((x)*(x))

#define sz(x) (int)x.size()

#define len(s) (int)(s.length())

#define all(a) a.begin(),a.end()

//=

int n,a[55][55],d[55][55],ans;

int main ()

{

    fr fw

    ios_base::sync_with_stdio(false);

    cin.tie(0);

    cin>>n;

    forr(1,n,i)

        forr(1,n,j)

            cin>>a[i][j];

    forr(1,n,i)

    {

        d[1][i]=a[i][1];

    }

    forr(2,n,j)

    {

        forr(1,n,si)

        {

            d[j][si]=d[j-1][si];

            forr(1,si,k)

            {

                d[j][si]=max(d[j][si],d[j-1][si-k]+a[k][j]);

            }

        }

    }

    cout<<d[n][n];

    return 0;

}