var f,g:text;
    st:array[1..20]of longint;
    a,b:array[1..20,1..20]of longint;
    n,m,k,i,j,max:longint;

procedure afis;
var l,w,s,s1:longint;
begin
for l:=1 to n do
    for w:=1 to m do
        b[l,w]:=a[l,w];
for l:=1 to n do
    if st[l]=-1 then for w:=1 to m do
                         b[l,w]:=b[l,w]*(-1);
s:=0;
for w:=1 to m do
    begin
    s1:=0;
    for l:=1 to n do
        s1:=s1+b[l,w];
    if s1<0 then s:=s-s1
            else s:=s+s1;
    end;
if s>max then max:=s;
end;

procedure back(k:longint);
var q:longint;
begin
if k<=n then for q:=1 to 2 do
                 begin
                 if q=1 then st[k]:=1
                        else st[k]:=-1;
                 back(k+1);
                 end
        else afis;
end;

begin
assign(f,'flip.in');reset(f);
assign(g,'flip.out');rewrite(g);
readln(f,n,m);
for i:=1 to n do
    for j:=1 to m do
        read(f,a[i,j]);
max:=-2000000000;
back(1);
writeln(g,max);
close(f);
close(g);
end.