type tabel=array[1..17,1..17] of longint;
		tab2=array[1..33] of longint;
var a,b:text;
	n,m,c,d,max:integer;
	t,u:tabel;
	s:tab2;

function calcul:longint;
var i,j:longint;
begin

for i:=1 to n do
if s[i]=1 then 
for j:=1 to m do
u[i,j]:=t[i,j]*(-1)
else
for j:=1 to m do
u[i,j]:=t[i,j];



for i:=n+1 to m+n do
if s[i]=1 then
for j:=1 to n do
u[j,i-n]:=t[j,i-n]*(-1)
else
for j:=1 to n do
if u[j,i-n]=0 then
u[j,i-n]:=t[j,i-n];

calcul:=0;
for i:=1 to n do
for j:=1 to m do
calcul:=calcul+u[i,j];

end;


procedure f(k:longint);
var i:integer;
begin
if k>0 then
begin
	if k-1=n+m then
		begin
		if calcul>max then max:=calcul;
		end
   	     else
		for i:=0 to 1 do
		begin
			s[k]:=i;
			f(k+1);
		end;
end;
end;


begin
assign(a,'flip.in'); reset(a);
assign(b,'flip.out'); rewrite(b);
read(a,n,m);
for c:=1 to n do
for d:=1 to m do
begin
read(a,t[c,d]);
end;
max:=0;
f(1);
writeln(b,max);


close(a);
close(b);
end.