var f,g:text;m,n,i,j:integer;s,sk:longint;a:array[1..16,1..16]of longint;
begin
assign(f,'flip.in');reset(f);
assign(g,'flip.out');rewrite(g);
read(f,n,m);
for i:=1 to n do
for j:=1 to m do read(f,a[i,j]);
for i:=1 to n do begin s:=0;sk:=0;
for j:=1 to m do begin
s:=s+a[i,j];sk:=sk+(a[i,j]*(-1));end;
if sk>s then for j:=1 to m do a[i,j]:=a[i,j]*(-1);end;
for j:=1 to m do begin s:=0;sk:=0;
for i:=1 to n do begin
s:=s+a[j,i];sk:=sk+(a[i,j]*(-1));end;
if sk>s then for i:=1 to n do a[j,i]:=a[j,i]*(-1);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.