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;
template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
  os << "[";
  for (auto u : v) {
    os << u;
    if (u != *v.rbegin()) os << ",";
  }
  os << "]" << endl;
  return os;
}
template <typename T>
ostream& operator<<(ostream& os, const multiset<T>& second) {
  os << "{";
  for (auto u : second) {
    os << u;
    if (u != *second.rbegin()) os << ",";
  }
  os << "}" << endl;
  return os;
}
template <typename T, typename U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
  os << "{";
  os << p.first << "," << p.second;
  os << "}" << endl;
  return os;
}
template <typename T, typename U>
ostream& operator<<(ostream& os, const map<T, U>& mp) {
  for (auto p : mp) os << p.first << " : " << p.second << endl;
  return os;
}
inline long long max(long long a, long long b) { return a > b ? a : b; }
inline long long min(long long a, long long b) { return a < b ? a : b; }
void boost() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
}
vector<pair<long long, long long>> mm;
bool cmp(pair<long long, long long>& a, pair<long long, long long>& b) {
  return mm[a.second - 1].second > mm[b.second - 1].second;
}
bool cmp1(pair<long long, long long>& a, pair<long long, long long>& b) {
  return mm[a.second - 1].second < mm[b.second - 1].second;
}
int32_t main() {
  boost();
  long long t = 1;
  while (t--) {
    long long n, a, b;
    vector<pair<long long, long long>> vp, vp1;
    cin >> n;
    for (long long i = 0; i < n; i++) {
      cin >> a >> b;
      mm.push_back({a, b});
      if (a < b)
        vp.push_back({b, i + 1});
      else {
        vp1.push_back({b, i + 1});
      }
    }
    sort(vp.begin(), vp.end(), cmp);
    sort(vp1.begin(), vp1.end(), cmp1);
    if (vp.size() >= vp1.size()) {
      cout << vp.size() << endl;
      for (auto ii : vp) {
        cout << ii.second << " ";
      }
    } else {
      cout << vp1.size() << endl;
      for (auto ii : vp1) {
        cout << ii.second << " ";
      }
    }
  }
  return 0;
}