N = int(input())
AB = [list(map(int, input().split())) for _ in range(N)]

nex = dict()
pre = -1
for i, (A, B) in enumerate(AB):
    if A == 1:
        nex[i+1] = i
    if B == 2:
        pre = i
    elif B == 1:
        nex[i] = pre

ans = []
for i, (A, B) in enumerate(AB):
    if A != 1 and B != 2:
        ans.append(i)
        now = i
        while now in nex:
            now = nex[now]
            ans.append(now)

for a in ans:
    print(a+1)