type tabb=array[1..35] of longint;
	tabval=array[1..17,1..17] of longint;
var a,b:text;
	t:tabb;
	u:tabval;
	c,r,i,j,max:longint;

procedure compsum(v:tabval);
var i,j,sum:longint;
begin
sum:=0;
for i:=1 to r do
if t[i]=1 then
for j:=1 to c do
v[i,j]:=v[i,j]*(-1);

for j:=r+1 to r+c do
if t[j]=1 then
for i:=1 to r do
v[i,j-r]:=v[i,j-r]*(-1);

for i:=1 to r do
for j:=1 to c do
sum:=sum+v[i,j];

if sum>max then max:=sum;
end;

procedure bk(k:longint);
var i:longint;
begin
if (k=c+r+1) then
compsum(u)
else
for i:=0 to 1 do
begin
t[k]:=i;
bk(k+1);
end;
end;

procedure citire;
begin
assign(a,'flip.in');
reset(a);
read(a,r,c);
max:=-260000000;

for i:=1 to r do
for j:=1 to c do
read(a,u[i,j]);

close(a);
end;

procedure scrie;
begin
assign(b,'flip.out');
rewrite(b);

writeln(b,max);

close(b);
end;

begin
citire;
bk(1);
scrie;
end.