var fi,fo:text;
    n,m,i,j:longint;
    v,aux:array[1..17,1..17] of longint;
    l1,l2,max,peak:longint;
    a,b:array[0..33000,1..15] of byte;



 function suma:longint;
   var i,j:longint;
       sum:longint;
     begin
     sum:=0;
      for i:=1 to n do
       for j:=1 to m do
         sum:=sum+aux[i,j];
      suma:=sum;
     end;

 procedure invcol(x:integer);
   var i:longint;
    begin
      for i:=1 to n do
        aux[i,x]:=-aux[i,x];
    end;

 procedure invlin(x:integer);
   var j:longint;
    begin
      for j:=1 to m do
        aux[x,j]:=-aux[x,j];
    end;

 procedure gosolve;
  var i,j,k,l:longint;
    begin
     for i:=0 to l1 do
      for j:=0 to l2 do
        begin
          aux:=v;
          for k:=1 to n do
            if a[i,k]=1 then invlin(k);
          for l:=1 to m do
            if b[j,l]=1 then invcol(l);
          peak:=suma;
          if peak>max then max:=peak;
        end;
    end;

 procedure b2I(x:longint);
  var int,i,j:longint;
   begin
     for i:=0 to x do
      begin
        int:=i;
        j:=1;
        while int<>0 do
          begin
            a[i,j]:=int mod 2;
            int:=int div 2;
            inc(j);
          end;
      end;

   end;

 procedure b2II(x:longint);
  var int,i,j:longint;
   begin
     for i:=0 to x do
      begin
        int:=i;
        j:=1;
        while int<>0 do
          begin
            b[i,j]:=int mod 2;
            int:=int div 2;
            inc(j);
          end;
      end;
   end;


 begin
  peak:=maxlongint;
  assign(fi,'flip.in'); reset(fi);
  assign(fo,'flip.out'); rewrite(fo);
  readln(fi,n,m);
  for i:=1 to n do
    for j:=1 to m do
     read(fi,v[i,j]);
  case n of
   1: l1:=1;
   2: l1:=3;
   3: l1:=7;
   4: l1:=15;
   5: l1:=31;
   6: l1:=63;
   7: l1:=127;
   8: l1:=255;
   9: l1:=511;
   10: l1:=1023;
   11: l1:=2047;
   12: l1:=4095;
   13: l1:=8191;
   14: l1:=16383;
   15: l1:=32767;
  end;
  b2I(l1);
  case m of
   1: l2:=1;
   2: l2:=3;
   3: l2:=7;
   4: l2:=15;
   5: l2:=31;
   6: l2:=63;
   7: l2:=127;
   8: l2:=255;
   9: l2:=511;
   10: l2:=1023;
   11: l2:=2047;
   12: l2:=4095;
   13: l2:=8191;
   14: l2:=16383;
   15: l2:=32767;
  end;
  b2II(l2);
{   for i:=0 to l1 do
    begin
     for j:=1 to n do
      write(fo,a[i,j],' ');
      writeln(fo);
    end;
   for i:=0 to l2 do
    begin
     for j:=1 to m do
      write(fo,b[i,j],' ');
    writeln(fo);
    end;}
  gosolve;
  writeln(fo,max);
  close(fi);
  close(fo);
 end.