program flip;
uses math;
var t:array[0..30,0..30] of longint;
    v:array[0..30] of longint;
    n,m,i,x,j,k,a,b,c,s_max,r:longint;
function suma:longint;
begin
        suma:=0;
        for j:=1 to m do
        begin
        r:=0;
        for i:=1 to n do
        r:=r+t[i,j]*v[i];
        suma:=suma+abs(r);
        end;
end;
procedure back(k:longint);
begin
        if (k=n+1) then s_max:=max(s_max,suma)
else
        begin
        v[k]:=1;
        back(k+1);
        v[k]:=-1;
        back(k+1);
        end;
end;
begin
       assign(input,'flip.in');
       assign(output,'flip.out');
       reset(input);
       rewrite(output);
       readln(n,m);
       for i:=1 to n do
       for j:=1 to m do
       read(t[i,j]);
       back(1);
       writeln(s_max);
       close(input);
       close(output);
end.