var f,g:text;     
    a:array[1..17,1..17] of longint;     
    x:array[0..17] of integer;     
    i,n,m,j,s,max,ss: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     
             begin     
             read(f,a[i,j]);     
             max:=max+a[i,j];     
             end;     
     while x[0]=0 do     
           begin     
                i:=n;     
                while x[i]=1 do begin x[i]:=0;i:=i-1; end;     
                x[i]:=1;     
                s:=0;     
                for j:=1 to m do     
                    begin     
                         ss:=0;     
                         for i:=1 to n do     
                             if x[i]=1 then ss:=ss-a[i,j]     
                                       else ss:=ss+a[i,j];     
                         if ss<0 then ss:=-ss;     
                         s:=s+ss;     
                    end;     
                if max<s then max:=s;     
           end;     
     writeln(g,max);     
close(f);     
close(g);   
end.