program Project2;

{$APPTYPE CONSOLE}

uses
  SysUtils;
 var n,k,i,j,max: integer;
 a: array [0..10000,0..10000] of integer;
begin
  { TODO -oUser -cConsole Main : Insert code here }
  assign(input,'legacy.in');
  reset(input);
  readln(n,k);
  for i:=1 to n do
    for j:=1 to n do
    read(a[i,j]);
  assign(output,'legacy.out');
  rewrite(output);
  max:=0;
for i:=n downto 1 do
for j:=n downto 1 do
if (a[i,j]> max) and (a[j,i]> max) then max:=max+a[i,j];

write (max);
end.