type matrice=array[1..50,1..50]of integer;
var a:matrice;
    f,g:text;
    i,j,m,n:integer;
function calcul(var a:matrice):integer;
var s1,s2,k,l:integer;
begin s2:=0;
 for i:=1 to n do begin{aici schimba linile}
   s1:=0;
   for j:=1 to m do s1:=s1+a[i,j];
   if s1<0 then begin
    for j:=1 to m do a[i,j]:=(a[i,j]*(-1));
    s1:=s1*(-1);
                end;
 end;
 for j:=1 to m do begin{aici schimba coloanele}
  s1:=0;
   for i:=1 to n do s1:=s1+a[i,j];
   if s1<0 then begin
    for i:=1 to n do a[i,j]:=a[i,j]*(-1);
    s1:=s1*(-1);
                end;
  s2:=s2+s1;{se face suma}
 end;
 calcul:=s2;
end;
begin
assign(f,'flip.in');reset(f);
assign(g,'flip.out');rewrite(g);
read(f,n);
read(f,m);
 for i:=1 to n do begin
  for j:=1 to m do
   read(f,a[i,j]);
   readln(f);end;
writeln;
write(g,calcul(a));
close(g);
write(calcul(a));
end.