program flip;
var f,g:text;
    a:array[1..20,1..20] of longint;
    n,m,i,j,x,s1,s:longint;
begin
assign(f,'flip.in');
assign(g,'flip.out');
reset(f);
rewrite(G);
read(f,n,m);
for i:=1 to n do
begin
readln(f);
for j:=1 to m do
read(f,a[i,j]);
end;

for i:=1 to n do
begin
s1:=0;s:=0;
for j:=1 to m do
begin
s1:=s1+a[i,j];
s:=s-a[i,j];
end;
if s>s1 then
for j:=1 to m do
a[i,j]:=a[i,j]*(-1);

for j:=1 to m do
begin
s1:=0;s:=0;
for x:=1 to n do
begin
s1:=s1+a[x,j];
S:=s-a[x,j];
end;
if s>s1 then
for x:=1 to n do
a[x,j]:=a[x,j]*(-1);
end;
end;

s:=0;
for i:=1 to n do
for j:=1 to m do
s:=s+a[i,j];
write(g,s);
close(f);
close(g);
end.