N=int(input())
from collections import deque
d=deque()

A=[]
for i in range(N):
  a,b=map(int,input().split())
  A.append((a,b))
  
C=[];c=10**10 
for i in range(N-1,-1,-1):
  a,b=A[i]
  if b==1:
    c=i 
  C.append(c)
C=C[::-1]
D=[-1]*N 
P=[-1]*N 
for i in range(N):
  a,b=A[i]
  if a==1:
    D[i+1]=i
    P[i]=i+1
  if b==2:
    D[C[i]]=i 
    P[i]=C[i]

ans=[]
for i in range(N):
  if P[i]==-1:
    now=i
    print(now+1)
    while True:
      nex=D[now]
      if nex==-1:
        break 
      print(nex+1)
      now=nex