{
    Jocul Flip
    Versiunea 4.00
}

Program Flip;

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

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

Procedure MaxL( i : Integer );
Var s1, s2 : Longint;
    j : Integer;
Begin
    s1 := 0;
    s2 := 0;
    For j := 1 to m do
        Begin
            s1 := s1 + a[i,j];
            s2 := s2 - a[i,j];
        End;

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

Procedure MaxC( j : Integer );
Var s1, s2 : Longint;
    i : Integer;
Begin
    s1 := 0;
    s2 := 0;
    For i := 1 to n do
        Begin
            s1 := s1 + a[i,j];
            s2 := s2 - a[i,j];
        End;

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


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

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

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