{
    Jocul Flip...
    Versiunea 2.00
}
Program Flip;

Type matrice = array[1..16,1..16] of Longint;

Var a : matrice;
    n, m, i, j, k : Byte;
    s, s1, s2 : Longint;

Begin
    Assign( input, 'flip.in' );
    Reset( input );
        Readln( n, m );
        For i := 1 to n do
            For j := 1 to m do
                Read( a[i,j] );
    Close( input );

    For i := 1 to n do
        For j := 1 to m do
            Begin
                s1 := 0;
                s2 := 0;
                For k := 1 to m do
                    Begin
                        s1 := s1 + a[i,k];
                        s2 := s2 - a[i,k];
                    End;
                if s2 > s1 then
                    For k := 1 to m do a[i,k] := -a[i,k];
                s1 := 0;
                s2 := 0;
                For k := 1 to n do
                    Begin
                        s1 := s1 + a[k,j];
                        s2 := s2 - a[k,j];
                    End;
                if s2 > s1 then
                    For k := 1 to n do a[k,j] := -a[k,j];
            End;

    s := 0;
    For i := 1 to n do
        For j := 1 to m do
            s := s + a[i,j];

    Assign( output, 'flip.out' );
    Rewrite( output );
        Writeln( s );
    Close( output );
End.