var v, w:array [1..20, 1..20] of longint;
    ww:array [1..20] of boolean;
    i, j, m, n, l, a, x:longint;
    s1, sum, max:longint;
    ok:boolean;
    f, g:text;

begin
assign (f, 'flip.in'); reset (f);
assign (g, 'flip.out'); rewrite (g);
max:=-maxlongint;
readln (f, n, m);
for i := 1 to n do
  for j := 1 to m do
    begin
    read (f, v[i, j]);
    end;

x:=1;
for i := 1 to n do x:=x*2;

for i := 0 to x-1 do
  begin
  a:=i;
  sum:=0;
  for j := 1 to n do
    begin
    if a mod 2 = 0 then
      begin
      for l := 1 to m do w[j, l] := v[j, l];
      end
                   else
      begin
      for l := 1 to m do w[j, l] := v[j, l]*(-1);
      end;
    a:=a div 2;
    end;
  for j := 1 to m do
    begin
    s1:=0;
    for l := 1 to n do s1:=s1+w[l, j];
    if s1>0 then sum := sum+s1
            else sum := sum-s1;
    end;
  if sum> max then max := sum;
  end;

writeln (g, max);
close (f); close (g);
end.