#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000003;
const long long INF = mod * mod;
const double eps = 1e-8;
const double pi = acos(-1.0);
bool comp(pair<pair<int, int>, int> a, pair<pair<int, int>, int> b) {
  pair<int, int> la = a.first, lb = b.first;
  if (la.second != lb.second) return la.second < lb.second;
  if (la.first != lb.first) return la.first < lb.first;
  return a.second < b.second;
}
void solve() {
  int n;
  cin >> n;
  vector<pair<int, int> > v(n);
  for (int i = 0; i < n; i++) cin >> v[i].first >> v[i].second;
  vector<pair<pair<int, int>, int> > le, ri;
  for (int i = 0; i < n; i++) {
    if (v[i].first > v[i].second) {
      le.push_back({v[i], i});
    } else {
      ri.push_back({v[i], i});
    }
  }
  if (le.size() >= ri.size()) {
    sort(le.begin(), le.end());
    cout << le.size() << endl;
    for (int i = 0; i < le.size(); i++) {
      if (i > 0) cout << " ";
      cout << le[i].second + 1;
    }
    cout << endl;
  } else {
    sort(ri.begin(), ri.end(), comp);
    cout << ri.size() << endl;
    for (int i = (int)ri.size() - 1; i >= 0; i--) {
      if (i < (int)ri.size() - 1) cout << " ";
      cout << ri[i].second + 1;
    }
    cout << endl;
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  solve();
  return 0;
}
