Program Flip;
var
	A:array[1..16,1..16] of longint;
	F,G:text;
	SB,SA:longint;
	M,N,I,J,jj:byte;
	con:integer;
	ST:longint;



Begin
For i:=1 to m do 
	for j:=1 to n do 
	A[i,j]:=0;
	N:=0; M:=0;
ASSIGN(F,'flip.in');
RESET(F);
READ(F,M,N);
for i:=1 to M do
	Begin
	For j:=1 to n do
	READ(F,A[i,j]);
	readln(F);
	end;
CLOSE(F);

SB:=0; SA:=0; con:=-1;



For i:=1 to N do
	Begin
   For j:=1 to M do
     begin
    SB:=SB+A[j,i];
	SA:=SA+(A[j,i]*con);
	 end;
	 if SA>SB then
			for jj:=1 to M do
			A[jj,i]:=A[jj,i]*con;
	SA:=0; SB:=0;
	end;

For i:=1 to M do
	Begin
   For j:=1 to N do
     begin
    SB:=SB+A[i,j];
	SA:=SA+(A[i,j]*con);
	 end;
	 if SA>SB then
			for jj:=1 to N do
			A[i,jj]:=A[i,jj]*con;
	SA:=0; SB:=0;
	end;

ST:=0;
For i:=1 to M do
	For j:=1 to N do
		ST:=ST+A[i,j];


ASSIGN(G,'flip.out');
rewrite(G);
write(G,St);
close(G);
end.