var n,m,i,j,k,ci,max:longint;  
        v,aux:array [1..17,1..17] of longint;  
      c,c2:array [1..16] of integer;  
    begin  
     assign(input,'flip.in'); reset(input);  
     assign(output,'flip.out'); rewrite(output);  
      readln(n,m);  
      for i:=1 to n do  
      for j:=1 to m do read(v[i,j]);  
     aux:=v;  
     for i:=0 to 1shl(m-1)-1 do begin  
      ci:=i;  
      for j:=1 to m do begin  
       c[j]:=ci mod 2; ci:=ci div 2;  
      end;  
      for j:=1 to n do  
       for k:=1 to m do  
        if c[k]=1 then v[j,17]:=v[j,17]+(v[j,k]*-1)  
                 else v[j,17]:=v[j,17]+v[j,k];  
     for j:=1 to n do v[17,17]:=v[17,17]+abs(v[j,17]);  
     if max<v[17,17] then max:=v[17,17];  
     v:=aux; c:=c2;  
    end;  
     writeln(max);  
    close(input); close(output);  
   end.