var n,m,sum:longint;
    a,b:array[1..16,1..16] of longint;
    
procedure bin(s:string);
var i,j,k,s1,s2:longint;
begin
  if length(s)=n then begin
    for i:=1 to n do 
      if s[i]='1' then 
        for j=1 to m do
          b[i,j]:=-a[i,j]
      else b[i,j]:=a[i,j];
    for k:=1 to m do begin
      s1:=0;
      s2:=0;
      for j:=1 to n do
        if a[j,k]>=0 then s1:=s1+a[j,k]
        else s2:=s2-a[j,k];
      if s2>s1 then
        for j:=1 to n do
          b[j,k]:=-a[j,k];
    for i:=1 to n do
      for j:=1 to m do
        k:=k+a[i,j];
    if k>sum then sum:=k;
  end else begin
    bin(s+'0');
    bin(s+'1');
  end;
end;
     
begin
//  assign(input,'input.in');
  assign(input,'flip.in');
  assign(output,'flip.out');
  reset(input);
  rewrite(output);
  read(n,m);
  for i:=1 to n do
    for j:=1 to m do read(a[i,j]);
  sum:=0;
  bin('');
  writeln(sum);
end.