program flip;
var A : array [1..16,1..16] of longint;
    B : array [1..32] of shortint;
    S : longint;
    m,n,i,j : byte;
    f : text;

procedure calc(p:integer);
var max:longint;
begin
max := 0;
for i := 1 to n do
for j := 1 to m do
A[i,j] := A[i,j]*B[i];

for i := 1 to m do
for j := 1 to n do
A[j,i] := A[j,i]*B[i+n];


for i := 1 to n do
for j := 1 to m do
max := max+A[i,j];

if max>S then S := max;

end;

procedure back(p:integer);
var pval : integer;
begin
for pval := 1 to 2 do begin
if pval=1 then B[p]:=1
          else B[p]:=-1;
if p=m+n then calc(p)
         else back(p+1);
end;
end;
begin
S := 0;
assign(f,'flip.in');
reset(f);
read(f,n);
readln(f,m);
for i := 1 to n do begin
for j := 1 to m do
read(f,A[i,j]);
readln(f);
end;
close(f);
back(1);
assign(f,'flip.out');
rewrite(f);
write(f,S);
close(f);

end.