var a:array[1..16,1..16] of longint;
    row,col:array[1..16] of longint;
    i,j,n,m,s,max,k,l,c:longint;
    f,g:text;
begin
assign(f,'flip.in');reset(f);
assign(g,'flip.out');rewrite(g);
readln(f,n,m);
for i:=1 to n do
  begin
    for j:=1 to m do
      read(f,a[i,j]);
    readln(f);
  end;
for i:=1 to (1 shl n)-1 do
  begin
    for l:=1 to m do
      col[l]:=0;
    s:=0;
    for j:=0 to n-1 do
      if (1 shl j) and i>0 then row[j+1]:=-1 else row[j+1]:=1;
    for l:=1 to n do
      for c:=1 to m do
        begin
        a[l,c]:=a[l,c]*row[l];
        col[c]:=col[c]+a[l,c];
        end;
    for l:=1 to m do
      if col[l]>0 then s:=s+col[l] else s:=s-col[l];
    if s>max then max:=s;
  end;
writeln(g,max);
close(f);close(g);
end.