Table

var
        a:array[1..500,1..500] of integer;
        n,sum,max,i,j,k,l:longint;
begin
        assign(input,'table.in');
        assign(output,'table.out');
        reset(input);
        rewrite(output);
        readln(n);
        max:=-1000000000;
        for i:=1 to n do begin
                for j:=1 to n do begin
                        read(a[i,j]);
                end;
                readln;
        end;
        for i:=1 to n do begin
        for k:=1 to n do begin
                j:=k;
                l:=i;
                sum:=0;
                while (j<=n) and (l<=n) do begin
                        sum:=sum+a[l,j];
                        if sum>max then max:=sum;
                        inc(j);
                        inc(l);
                end;
        end;
        end;
        for i:=n downto 1 do begin
        for k:=1 to n do begin
                j:=k;
                l:=i;
                sum:=0;
                while (j<=n) and (l>=1) do begin
                        sum:=sum+a[l,j];
                        if sum > max then max:=sum;
                        inc(j);
                        dec(l);
                end;
        end;
        end;
        writeln(max);
        close(input);
        close(output);
end.