const true=1,false=0;
var x,y,m,n,pf;
procedure prime;
var i,f;
  procedure mod;
    x:=x-x/y*y;
  begin
   f:=true;
   i:= 3;
   while i<m do
     begin
       x:=m;
       y:=i;
       call mod;
       if x=0 then f:=false;
       i:=i+2;
     end;
   if f=true then
     begin
       write(m);
       pf:=true;
     end;
  end;
begin
  pf:=false;
  read(n);
  while n>=2 do
  begin
    write(2);
    if n=2 then pf:=true;
    m:=3;
    while m<=n do
      begin
        call prime;
        m:=m+2;
      end;
    read(n);
  end;
  if pf = false then write(0);
end.