from heapq import heapify, heappop, heappush
from collections import defaultdict 
from collections import deque

class UnionFind(object):
    def __init__(self, n=1):
        self.par = [i for i in range(n)]
        self.rank = [0 for _ in range(n)]
        self.size = [1 for _ in range(n)]
    def find(self, x):
        """
        x が属するグループを探索して親を出す。
        """
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]
    def union(self, x, y):
        """
        x と y のグループを結合
        """
        x = self.find(x)
        y = self.find(y)
        if x != y:
            if self.rank[x] < self.rank[y]:
                x, y = y, x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
            self.par[y] = x
            self.size[x] += self.size[y]
    def is_same(self, x, y):
        """
        x と y が同じグループか否か
        """
        return self.find(x) == self.find(y)
    def get_size(self, x):
        """
        x が属するグループの要素数
        """
        x = self.find(x)
        return self.size[x]


def main():
    N = int(input())
    deg = [0]*N
    dic = defaultdict(list)
    uf = UnionFind(N)
    for i in range(N):
        a,b = map(int,input().split())
        a -= 1; b -= 1
        deg[a] += 1
        deg[b] += 1
        dic[a].append((b,i)) #行先、辺の番号
        dic[b].append((a,i))
        uf.union(a,b)
    G = [[] for _ in range(N)]
    PL = set([])
    for i in range(N):
        par = uf.find(i)
        PL.add(par)
        heappush(G[par], (deg[i],i))
    #print(G)
    Q = deque([])
    #for i in range(N):
    #    heappush(PQ,(deg[i],i))
    ret = []
    used_point = set([])
    used_edge = set([])
    for par in PL:
        Q = []
        d,i = heappop(G[par])
        if i in used_point: continue
        heappush(Q,(d,i))
        while G[par] and G[par][0][0] == 1: #出る数が1なら追加
            d,i = heappop(G[par])
            if i in used_point: continue
            heappush(Q,(d,i))
        while Q:
            d,v = heappop(Q)
            #print("v",v)
            if v in used_point: continue
            for u,edge_idx in dic[v]:
                #print(u,edge_idx,used_edge)
                if edge_idx in used_edge: continue
                ret.append(v)
                used_point.add(v)
                used_edge.add(edge_idx)
                deg[v] -= 1
                deg[u] -= 1
                if u not in used_point:
                    heappush(Q,(deg[u],u))
                break
    #print(ret)
    if len(ret) == N:
        print('Yes')
        ret = [x+1 for x in ret]
        print(*ret,sep="\n")
    else:
        print('No')

if __name__ == '__main__':
    main()