type  matrice=array[1..5,1..3]of integer;

procedure citire (var a:matrice; var n:byte; var m:byte);
var i,j:byte;
    f:text;
begin
assign(f,'flip.in');reset(f);
readln(f,n,m);
for i:=1 to n do
begin
   for j:=1 to m do
     read(f,a[i,j]);
readln(f);
end;
close(f);
end;
procedure a1 (var a:matrice; n,m:integer);
var  i,s1,s2,j,k:longint;
begin
for i:=1 to n do
begin
   s1:=0;s2:=0;
  for j:=1 to m do

     if a[i,j]<0 then  s2:=s2+a[i,j]
                 else s1:=s1+a[i,j];
     s2:=s2*s2;
     s2:=trunc(sqrt(s2));
     if s2>s1 then
       for k:=1 to m do
         a[i,j]:=a[i,j]*-1;

end;
end;
procedure a2 (var a:matrice; n,m:integer);
var s1,s2,i,j,k:longint;
begin
for i:=1 to m do
begin
  s1:=0;s2:=0;
  for j:=1 to n do

    if a[j,i]<0 then   s2:=s2+a[j,i]
                else   s1:=s1+a[j,i];
                s2:=s2*s2;
     s2:=trunc(sqrt(s2));

    if s2>s1 then
       for  k:=1 to n do
         a[k,j]:=a[k,j]*-1;

end;
end;
var  i,j,s:longint;
    a:matrice;
    n,m:byte;
    g:text;
begin
citire (a,n,m);
a1(a,n,m);
a2(a,n,m);
assign(g,'flip.out');rewrite(g);
for i:=1 to n do
 for j:=1 to m do
     s:=s+a[i,j];
write(g,s);
close(g);
end.