var f,g:text;
m,n:integer;
a:array[1..16,1..16] of longint;
s,x,y:longint;
i,j:integer;
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
                x:=0;y:=0;
                for j:=1 to m do
                        if a[i,j]>0 then
                                x:=x+a[i,j]
                        else
                                y:=y+a[i,j];
                if x<abs(y) then
                        for j:=1 to m do
                                a[i,j]:=-1*a[i,j];
                end;
        for i:=1 to m do  begin
                x:=0;
                y:=0;
                for j:=1 to n do
                        if a[j,i]>0 then
                                x:=x+a[j,i]
                        else
                                y:=y+a[j,i];
                if x>abs(y) then
                        s:=s+x
                else
                        s:=s+abs(y);
        end;
        write (g,s);
        close(g);
end.