sub muri{
	print"No\n";
	exit;
}

$n=<>;

@evv=map{
	($a,$b)=<>=~/\w+/g;
	push@$a,$_;
	push@$b,$_;
	$a+$b;
}0..$n-1;

@vn=map~~@$_,0..$n;
@q=grep$vn[$_]==1,1..$n;

while(@q){
	$vi=pop@q;
	$vn[$vi]=-1;
	for$ei(grep!$ans[$_],@$vi){
		$vj=$evv[$ei]-$vi;
		$d=--$vn[$vj];
		if($d==0){
			muri;
		}
		$ans[$ei]=$vi;
		if($d==1){
			push@q,$vj;
		}
	}
}

for$vi(1..$n){
	if($vn[$vi]>=0){
		$vo=$vi;
		do{
			$vn[$vi]=-1;
			for$ei(grep!$ans[$_],@$vi){
				$ans[$ei]=$vi;
				$vi=$evv[$ei]-$vi;
				goto hoge;
			}
			muri;
			hoge:;
		}while($vi!=$vo);
	}
}

print $_,$/ for Yes,@ans;