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

def main():
    N = int(input())
    deg = [0]*N
    dic = defaultdict(list)
    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))
    PQ = []
    for i in range(N):
        heappush(PQ,(deg[i],i))
    Q = deque([])
    #for i in range(N):
    #    heappush(PQ,(deg[i],i))
    ret = []
    used_point = set([])
    used_edge = set([])
    while PQ:
        d,i = heappop(PQ)
        if i in used_point: continue
        Q.append(i)
        while Q:
            v = Q.popleft()
            #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)
                if u not in used_point:
                    Q.append(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()