from collections import defaultdict
N = int(input())
moji = []
for _ in range(N):
    a,b = list(map(int,input().split()))
    moji.append((a,b))

ans = []
stack = []
onetwo = []
must = defaultdict(list)
for i in range(N):
    a,b = moji[i]
    if(a == 1 and b == 0):
        stack.append(i)
    elif(a == 1 and b == 1):
        stack.append(onetwo.pop())
        stack.append(i)
    elif(a == 0 and b == 2):
        onetwo.append(i)
        if(stack):
            must[i] += stack.copy()
            stack = []
    elif(a == 0 and b == 1):
        ans.append(i)
        v = onetwo.pop()
        ans.append(v)
        while(must[v]):ans.append(must[v].pop())
    elif(a == 0 and b == 0):
        ans.append(i)
        while(stack):
            v = stack.pop()
            ans.append(v)
            for i in must[v]:
                ans.append(i)
    else:
        1/0

for i in ans:
    print(i+1)