#include<iostream>
#include<vector>
using namespace std;
using ll = long long;

int main(){
    int N;
    cin >> N;
    vector<bool> lock(N,0);
    vector<int> to(N,-1);
    int two = -1;
    for(int i = 0; i < N; i++){
        int A,B;
        cin >> A >> B;
        if(A == 1){
            lock[i] = 1;
            to[i+1] = i;
        }
        if(B == 1){
            to[i] = two;
        }
        if(B == 2){
            lock[i] = 1;
            two = i;
        }
    }

    for(int i = 0; i < N; i++){
        if(!lock[i]){
            cout << i + 1 << endl;
            int now = i;
            while(to[now] != -1){
                now = to[now];
                cout << now + 1 << endl;
            }
        }
    }
    return 0;
}