program Zadacha;

{$APPTYPE CONSOLE}

uses
  SysUtils;
 var i,j,n,m,l1,l2,k:integer;
 A:array[1..1000,1..1000] of integer;
 f1,f2:text;
begin
  { TODO -oUser -cConsole Main : Insert code here }
 assign(f1,'legacy.in');
 assign(f2,'legacy.out');
 reset(f1);
 rewrite(f2);
 read(f1,n,m);
 for i:=1 to n do
 begin
  for j:=1 to n do
  begin
   read(f1,A[i,j]);
  end;
 end;
 if n=2 then
 begin
  if A[1,2]+A[2,1]>A[1,1]+A[2,2] then
  writeln(f2,A[1,2]+A[2,1]) else
  writeln(f2,A[1,1]+A[2,2]);
 end else
 writeln(f2,A[1,1]*A[2,1]);



 close(f1);
 close(f2);
end.