Program Flip;
Type lungime=-1000000..1000000;
var
    A:array[1..16,1..16] of lungime;
    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.