program flipuri;
var a,b:array[1..17] of integer;
v:array[1..16,1..16] of longint;
n,m,i,j:integer;
sum,sum1,sum2,summax:longint;
f,g:text;
begin
  assign(f,'flip.in'); assign(g,'flip.out');
  reset(f); rewrite(g);
  read(f,n,m);
  for i:=1 to n do
    for j:=1 to m do
      read(f,v[i,j]);
  summax:=-2000000000;
  a[1]:=-1;
  repeat
    a[1]:=a[1]+1;
    i:=1;
    while a[i]=2 do
    begin
      a[i]:=0;
      i:=i+1;
      a[i]:=a[i]+1;
    end;
    sum:=0;
    if a[n+1]<>1 then
    for i:=1 to m do
      begin
        sum1:=0; sum2:=0;
        for j:=1 to n do
          if a[j]=1 then sum1:=sum1-v[j,i]
                    else sum1:=sum1+v[j,i];

        if sum1>0 then sum:=sum+sum1 else sum:=-sum1+sum;
      end;
    if sum>summax then summax:=sum;
  until a[n+1]=1;
  writeln(g,summax);
  close(f); close(g);
end.