Var n,m,i,j,q,w,max,s,s1,k:Longint;
    f,g:Text;
    a:array[1..100,1..100] of Longint;

Begin

Assign(f,'flip.in'); ReSet(f);
Assign(g,'flip.out'); ReWrite(g);

Read(f,n,m);

For i:=1 To n Do
    For j:=1 To m Do
        Read(f,a[i,j]);

max:=0;

For i:=1 To n Do
    For j:=1 To m Do Begin
        s:=0;
        s1:=0;
        For k:=1 To m Do
            If a[i,k]<0 Then Inc(s,a[i,k])
                        Else Inc(s1,a[i,k]);
        For k:=1 To n Do
            If a[k,j]<0 Then Inc(s,a[k,j])
                        Else Inc(s1,a[k,j]);
        If (s<max)and(abs(s)>s1) Then Begin
           max:=s;
           q:=i;
           w:=j;
           End;
        End;

For i:=1 To m Do
    a[q,i]:=a[q,i]*(-1);
For i:=1 To n Do
    a[i,w]:=a[i,w]*(-1);
a[q,w]:=a[q,w]*(-1);

s:=0;

For i:=1 To n Do
    For j:=1 To m Do
        s:=s+a[i,j];

WriteLn(g,s);

Close(f);
Close(g);

End.