program flip;

var a : array[1..17,1..17] of longint;
    d : array[1..17] of shortint;
    l,c,i,j : byte;
    s : longint;
    f : text;

procedure suma;
var st,sc : longint;
    i,j : byte;
begin
    st := 0;
    for i := 1 to c do begin
         sc := 0;
         for j := 1 to l do sc := sc+(d[j]*a[j,i]);
         if sc > 0 then st := st+sc
         else st := st-sc;
         end;
    if st > s then s := st;
end;

procedure back;
var k : byte;
begin
    k := 1; d[k] := -3;
    while k > 0 do begin
        while d[k] < 1 do begin
            d[k] := d[k]+2;
            if k = l then suma
            else begin
                k := k+1;
                d[k] := -3;
                end;
            end;
        k := k-1;
        end;
end;

begin
    assign(f,'flip.in'); reset(f);

    readln(f,l,c);
    for i := 1 to l do begin
        for j := 1 to c do read(f,a[i,j]);
        readln(f);
        end;
    close(f);

    back;

    assign(f,'flip.out'); rewrite(f);
    write(f,s);
    close(f);
end.