program flip;
var m,n,i,j:byte;
    s,ss,smax:longint;
    a:array[1..16,1..16] of longint;
    x:array[1..32]of integer;
    f,h:text;
begin
assign(f,'flip.in');
assign(h,'flip.out');
reset(f);rewrite(h);
readln(f,n,m);
for i:=1 to n do
 for j:=1 to m do read(f,a[i,j]);
ss:=0;
for i:=1 to n do
 begin
 s:=0;
 for j:=1 to m do s:=s+a[i,j];
 if s<0 then x[i]:=1;
 end;
for i:=1 to m do
 begin
 s:=0;
 for j:=1 to n do
  if x[j]=0 then s:=s+a[i,j]
            else s:=s-a[i,j];
 if s<0 then x[n+i]:=1;
 end;
smax:=0;
for i:=1 to n do
 for j:=1 to m do
  if ((x[i]=1)and(x[n+j]=1))or
     ((x[i]=0)and(x[n+j]=0))
            then smax:=smax+a[i,j]
            else smax:=smax-a[i,j];
writeln(h,smax);
close(f);close(h);
end.