import java.util.Scanner;
import java.util.List;
import java.util.ArrayList;
import java.util.Arrays;

public class No1640 {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		N = Integer.valueOf(scan.nextLine());
		G = new ArrayList<List<Integer>>();
		for (int i=0; i < 2*N; i++) {
			G.add(new ArrayList<Integer>());
		}
		match = new int[2*N];
		Arrays.fill(match, -1);
		used = new boolean[2*N];
		for (int i=0; i < N; i++) {
			String[] s = scan.nextLine().split(" ");
			add_edge(i, Integer.valueOf(s[0]) + N - 1);
			add_edge(i, Integer.valueOf(s[1]) + N - 1);
		}
		int n = bipartite_matching();
		if (n == N) {
			System.out.println("Yes");
			for (int i=0; i < N; i++) {
				System.out.println(match[i] - N + 1);
			}
		} else {
			System.out.println("No");
		}
	}
	
	private static int N;
	private static List<List<Integer>> G;
	private static int[] match;
	private static boolean[] used;
	
	private static void add_edge(int u, int v) {
		G.get(u).add(v);
		G.get(v).add(u);
	}
	
	private static boolean dfs(int v) {
		used[v] = true;
		for (int u : G.get(v)) {
			int w = match[u];
			if (w < 0 || (!used[w] && dfs(w))) {
				match[v] = u;
				match[u] = v;
				return true;
			}
		}
		return false;
	}
	
	private static int bipartite_matching() {
		int res = 0;
		for (int v=0; v < 2*N; v++) {
			if (match[v] < 0) {
				Arrays.fill(used, false);
				if (dfs(v)) {
					res++;
				}
			}
		}
		return res;
	}
}