program fackt;
var x,p:longint;
    t,f:text;
begin
  assign(f,'fact.in');
  reset(f);
  assign(t,'fact.out');
  rewrite(t);
  read(f,p)
  {--------------------}
  case p of
  0 :x:=1;
  1 :x:=5;
  2 :x:=10;
  3 :x:=15;
  4..100000000:
    begin
      x:=p*5;
    end;
  end;
  {--------------------}
  write(t,x);
  close(f);
  close(t);
end.