{Jocul FLIP. www.InfoArena.pas}

type VECTOR  = array[1..16] of longint;
     MATRICE = array[1..16] of VECTOR;

var n,m  : byte;
    A    : MATRICE;
    L    : VECTOR;   {sumele pe linii}
    C    : VECTOR;   {sumele pe coloane}
    smax : longint;

procedure Citire;
var i,j : byte;
    f   : text;
begin
     Assign(f,'flip.in'); Reset(f);
     Readln(f,n,m);
     for i:=1 to n do L[i]:=0;
     for j:=1 to m do C[j]:=0;
     smax := 0;
     for i:=1 to n do
         for j:=1 to m do
             begin
                  Read(f,A[i,j]);
                  L[i] := L[i] + A[i,j];
                  C[j] := C[j] + A[i,j];
                  smax := smax + A[i,j];
             end;
     Close(f);
end;

procedure AflaMinimNegativ(var min:longint; var unde, p : byte);
var i, j : byte;
    {unde : byte; 1 => in L; 2 => in C}
    {p    : byte; pozitia minimului}
begin
     min := MaxLongInt;
     {trec pe la linii}
     for i:=1 to n do if L[i] < min then
         begin
              min:=L[i]; p:=i; unde:=1;
         end;
     {trec pe la coloane}
     for j:=1 to m do if C[j] < min then
         begin
              min:=C[j]; p:=j; unde:=2;
         end;
     case unde of
          1 : L[p] := -L[p];
          2 : C[p] := -C[p];
     end;
end;

procedure CorecteazaLiniile(p:byte);
var i : byte;
    s : longint;
begin
     S:=0;
     for i:=1 to n do
         begin
              L[i]:=L[i] - 2 * A[i,p];
              S := S + L[i];
              A[i,p]:=-A[i,p];
         end;
     if S > Smax then Smax := s;
end;

procedure CorecteazaColoanele(p:byte);
var s : longint; j:byte;
begin
     S:=0;
     for j:=1 to m do
         begin
              C[j]:=C[j] - 2 * A[p,j];
              S := S + C[j];
              A[p,j]:=-A[p,j];
         end;
     if S > Smax then Smax := s;
end;

var min     : longint;
    unde, p : byte;
    f       : text;

begin
     Citire;
     repeat
           AflaMinimNegativ(min, unde, p);
           if min < 0 then
              case unde of
                  1 : {pe linie}   CorecteazaColoanele(p);
                  2 : {pe coloana} CorecteazaLiniile(p);
              end;
     until min>=0;
     Assign(f,'flip.out'); ReWrite(f); Write(f,smax); Close(f);
end.