N=int(input())
stack=[]
for i in range(1,N+1):
    A,B=map(int,input().split())
    if A==0:
        if B==0:
            print(i)
            while len(stack) and stack[-1][0][0]==1:
                (a,b),ii=stack.pop()
                print(ii)
                if b==1:
                    print(stack.pop()[1])
        elif B==1:
            print(i)
            print(stack.pop()[1])
        else:
            stack.append(((0,2),i))
    else:
        if B==0:
            stack.append(((1,0),i))
        elif B==1:
            stack.append(((1,1),i))
while len(stack):
    print(stack.pop()[1])