program flip;
var m,n,i,j:byte;
    smax,s:longint;
    a:array[1..16,1..16] of longint;
    x:array[1..32]of integer;
    f,h:text;
function cond(k:integer):boolean;
var i:byte;
    s:longint;
begin
 s:=0;
 if k<=m then
   for i:=1 to n do s:=s+a[i,k]
 else for i:=1 to m do
      if x[i]=0 then s:=s+a[k-m,i]
                else s:=s-a[k-m,i];
    if x[k]=1 then s:=s*(-1);
   cond:=s>=0;
end;
function sol(k:integer):boolean;
begin
sol:=k=m+n;
end;
function tipar:longint;
var s:longint;
    i,j:integer;
begin
s:=0;
for i:=1 to n do
 for j:=1 to m do
  if ((x[j]=1)and(x[m+i]=1))or
     ((x[j]=0)and(x[m+i]=0))
            then s:=s+a[i,j]
            else s:=s-a[i,j];
tipar:=s;
end;
procedure back;
var k:integer;
begin
 k:=1;x[k]:=-1;
 while k>0 do
  if x[k]<1 then
  begin
   x[k]:=x[k]+1;
   if cond(k) then
     if sol(k) then begin
                     s:=tipar;
                     if smax<s then smax:=s;
                    end
               else begin
                     inc(k);
                     x[k]:=-1;
                    end;
  end
  else dec(k);
end;
begin
assign(f,'flip.in');
assign(h,'flip.out');
reset(f);rewrite(h);
readln(f,n,m);
for i:=1 to n do
 for j:=1 to m do read(f,a[i,j]);
back;
writeln(h,smax);
close(f);close(h);
end.