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.