program flip;   
type matrice = array [1..17,1..17] of longint;   
var x:matrice;   
    i,j:integer;   
    mm,max,ma,n,m:longint;   
    fin,fout:text;   
begin  
  assign(fin,'flip.in');   
  assign(fout,'flip.out');   
  reset(fin);   
  rewrite(fout);   
  readln(fin,n,m);   
  for i:=1 to n do  
    begin  
      for j:=1 to m do  
        read(fin,x[i,j]);   
      readln(fin);   
    end;   
  
  for i:=1 to m do  
    begin  
      ma:=0;   
      mm:=0;   
      for j:=1 to n do  
        begin  
          ma:=ma+x[j,i];   
          mm:=mm+x[j,i]*-1;   
        end;   
      if mm > ma then  
        begin  
          for j:=1 to n do  
            begin  
              x[j,i]:=x[j,i]*-1;   
            end;   
        end;   
    end;   
  max:=0;   
  for i:=1 to n do  
    begin  
      ma:=0;   
      mm:=0;   
      for j:=1 to m do  
        begin  
          ma:=ma+x[i,j];   
          mm:=mm+x[i,j]*-1;   
        end;   
      if mm > ma then  
        begin  
          for j:=1 to m do  
            begin  
              x[i,j]:=x[i,j]*-1;   
            end;   
        end;   
    end;   
  for i:=1 to m do  
    begin  
      ma:=0;   
      mm:=0;   
      for j:=1 to n do  
        begin  
          ma:=ma+x[j,i];   
          mm:=mm+x[j,i]*-1;   
        end;   
      if mm > ma then  
        begin  
          for j:=1 to n do  
            begin  
              x[j,i]:=x[j,i]*-1;   
            end;   
        end;   
    end;   
  for i:=1 to n do  
    begin  
      for j:=1 to m do  
        max:=max+x[i,j];   
    end;   
  writeln(fout,max);   
  close(fout);   
end.