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]==1:
                print(stack.pop()[1])
        elif B==1:
            print(i)
            print(stack.pop()[1])
        else:
            stack.append((2,i))
    else:stack.append((1,i))
while len(stack):
    print(stack.pop()[1])