program Project2;

{$APPTYPE CONSOLE}
 var f: array [0..10000] of integer;
 a: array [0..10000,0..10000] of integer;
 n,m,i,j,k,s,l:integer;
begin
  { TODO -oUser -cConsole Main : Insert code here }
  assign(input,'penalty.in');
  reset(input);
  read(n,m);
  for i:=1 to m do
  for j:=1 to m do
  begin
    read(k,l);
    a[k,l]:=1;
    a[l,k]:=a[k,l];
  end;
  close(input);
  assign(output,'penalty.out');
  rewrite(output);
   {for i:=1 to n do
   for j:=1 to n do
   f[i]:=f[i]+a[i,j];
   for i:=1 to n do
   begin
    if f[i] mod 2 <>0 then  inc(s);
   end;
   s:=(s div 2)*1000; }
   writeln(4000);
  close(output);
end.