Problem: You are given n pairs of integers (a_1, b_1), (a_2, b_2), …, (a_n, b_n). All of the integers in the pairs are distinct and are in the range from 1 to 2 ⋅ n inclusive.

Let's call a sequence of integers x_1, x_2, …, x_{2k} good if either 

  * x_1 < x_2 > x_3 < … < x_{2k-2} > x_{2k-1} < x_{2k}, or 
  * x_1 > x_2 < x_3 > … > x_{2k-2} < x_{2k-1} > x_{2k}. 



You need to choose a subset of distinct indices i_1, i_2, …, i_t and their order in a way that if you write down all numbers from the pairs in a single sequence (the sequence would be a_{i_1}, b_{i_1}, a_{i_2}, b_{i_2}, …, a_{i_t}, b_{i_t}), this sequence is good.

What is the largest subset of indices you can choose? You also need to construct the corresponding index sequence i_1, i_2, …, i_t.

Input

The first line contains single integer n (2 ≤ n ≤ 3 ⋅ 10^5) — the number of pairs.

Each of the next n lines contain two numbers — a_i and b_i (1 ≤ a_i, b_i ≤ 2 ⋅ n) — the elements of the pairs.

It is guaranteed that all integers in the pairs are distinct, that is, every integer from 1 to 2 ⋅ n is mentioned exactly once.

Output

In the first line print a single integer t — the number of pairs in the answer.

Then print t distinct integers i_1, i_2, …, i_t — the indexes of pairs in the corresponding order.

Examples

Input


5
1 7
6 4
2 10
9 8
3 5


Output


3
1 5 3


Input


3
5 4
3 2
6 1


Output


3
3 2 1

Note

The final sequence in the first example is 1 < 7 > 3 < 5 > 2 < 10.

The final sequence in the second example is 6 > 1 < 3 > 2 < 5 > 4.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
const long long int N = 1e5 + 2;
const long long int INF = 1e9 + 9;
const long long int mod = 1e9 + 7;
void solve() {
  long long int n;
  cin >> n;
  long long int i, a, b, r;
  vector<pair<pair<long long int, long long int>, long long int>> vec1, vec2;
  for (i = 1; i <= n; i++) {
    cin >> a >> b;
    if (a < b)
      vec1.push_back(make_pair(make_pair(-a, b), i));
    else
      vec2.push_back(make_pair(make_pair(b, a), i));
  }
  sort((vec1).begin(), (vec1).end());
  sort((vec2).begin(), (vec2).end());
  if (vec1.size() > vec2.size()) {
    cout << vec1.size() << '\n';
    for (auto i : vec1) cout << i.second << " ";
    cout << '\n';
  } else {
    cout << vec2.size() << '\n';
    for (auto i : vec2) cout << i.second << " ";
    cout << '\n';
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ;
  long long int t = 1;
  for (long long int i = 1; i <= t; i++) {
    solve();
  }
}