var a:array[0..20,0..16] of longint;
    f:text;
    i,smax,j,m,n:integer;
{------------------}
procedure suma;
begin
     assign(f,'flip.in');
     reset(f);
     readln(f,n,m);
     for i:=1 to n do
         for j:=1 to m do begin
             read(f,a[i,j]);
             a[0,j]:=a[0,j]+a[i,j];
             a[i,0]:=a[i,0]+a[i,j];
             smax:=smax+a[i,j];
             end;
close(f);
end;
{------------------}
begin
suma;
for i:=1 to n do
    if a[i,0]<0 then
       for j:=1 to m do begin
           a[i,j]:=a[i,j]*(-1);
           a[i,0]:=a[i,0]+2*a[i,j];
           smax:=smax+2*a[i,j];
           a[0,j]:=a[0,j]+2*a[i,j];
           end;
for i:=1 to m do
    if a[0,i]<0 then
       for j:=1 to n do begin
           a[j,i]:=a[j,i]*(-1);
           a[j,0]:=a[j,0]+2*a[j,i];
           smax:=smax+2*a[j,i];
           a[0,i]:=a[0,i]+2*a[j,i];
           end;
assign(f,'flip.out');
rewrite(f);
write(f,smax);
close(f);
end.