#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9;
const int maxn = 3e5 + 100;
bool ok(const std::vector<long long> &a, const std::vector<long long> &b,
        int ind_b, int k) {
  int need = INF;
  for (int i = 0; i < a.size() && a[i] <= b[ind_b]; ++i) {
    auto it = lower_bound(b.begin(), b.begin() + ind_b, a[i]);
    int del_b = ind_b - (it - b.begin());
    int del_a = i;
    need = min(need, del_a + del_b);
  }
  return need <= k;
}
vector<pair<int, int>> ans;
int obr[maxn];
void swap_p(vector<int> &p, int a, int b) {
  if (a == b) {
    return;
  }
  ans.emplace_back(a, b);
  swap(p[a], p[b]);
  obr[p[a]] = a;
  obr[p[b]] = b;
}
int main() {
  int n;
  cin >> n;
  vector<pair<int, int>> pp;
  for (int i = 1; i <= n; ++i) {
    int a, b;
    cin >> a >> b;
    pp.emplace_back(a, b);
  }
  vector<int> ind_increasing;
  vector<int> ind_decreasing;
  for (int i = 0; i < n; ++i) {
    if (pp[i].first < pp[i].second) {
      ind_increasing.push_back(i);
    } else {
      ind_decreasing.push_back(i);
    }
  }
  if (ind_increasing.size() > ind_decreasing.size()) {
    vector<pair<int, int>> sorted_ind;
    for (int ind : ind_increasing) {
      sorted_ind.push_back({pp[ind].first, ind});
    }
    sort(sorted_ind.begin(), sorted_ind.end());
    cout << ind_increasing.size() << "\n";
    for (int i = sorted_ind.size() - 1; i >= 0; --i) {
      cout << sorted_ind[i].second + 1 << " ";
    }
  } else {
    vector<pair<int, int>> sorted_ind;
    for (int ind : ind_decreasing) {
      sorted_ind.push_back({pp[ind].first, ind});
    }
    sort(sorted_ind.begin(), sorted_ind.end());
    cout << ind_decreasing.size() << "\n";
    for (int i = 0; i < sorted_ind.size(); ++i) {
      cout << sorted_ind[i].second + 1 << " ";
    }
  }
}
