$|=1;
print 0 x10,$/;
$r=<>;
exit if$r=~u;

for$a(0..9){
	for$d(0..9){
		print'0'x$a,$d,'0'x(9-$a),$/;
		$s=<>;
		exit if$s=~u;
		if($r>$s){
			$b.=0;
			last;
		}
		if($r<$s){
			$b.=$d;
			last;
		}
	}
}
print $b,$/;