program joc;
type vector=array[1..16,1..16] of longint;
     subm=array[0..16] of shortint;
var a:vector;
    v:subm;
    n,m,i,j:byte;
    smax:longint;

procedure calcul;
var s:longint;
    aux:array[1..16] of longint;
    i,j:byte;
begin
s:=0;
for i:=1 to m do aux[i]:=0;
for i:=1 to n do
        for j:=1 to m do aux[j]:=aux[j]+a[i,j]*v[i];
for i:=1 to m do
        if aux[i]<0 then s:=s-aux[i]
                    else s:=s+aux[i];
if s>smax then smax:=s;
end;

procedure back(k:byte);
begin
if k=n+1 then calcul
         else begin
              v[k]:=-1;
              back(k+1);
              v[k]:=1;
              back(k+1)
              end;
end;

begin
assign(input,'flip.in'); reset(input);
assign(output,'flip.out'); rewrite(output);
readln(n,m);
for i:=1 to n do begin
        for j:=1 to m do begin
                         read(a[i,j]);
                         smax:=smax+a[i,j];
                         end;
        readln;
                end;
close(input);
back(1);
write(smax);
close(output);
end.