#include <bits/stdc++.h>
using namespace std;
using ii = pair<int, int>;
using ll = long long;
using vi = vector<int>;
template <typename T>
using minheap = priority_queue<T, vector<T>, greater<T>>;
template <typename T>
using maxheap = priority_queue<T>;
template <typename T>
ostream& operator<<(ostream& os, vector<T> v) {
  os << "[ ";
  for (auto e : v) os << e << " ";
  return os << "]";
}
template <typename T, typename V>
ostream& operator<<(ostream& os, set<T, V> v) {
  os << "{ ";
  for (auto e : v) os << e << " ";
  return os << "}";
}
template <typename T, typename V, typename S>
ostream& operator<<(ostream& os, map<T, V, S> v) {
  os << "{ ";
  for (auto e : v) os << e << " ";
  return os << "}";
}
template <typename T, typename V>
ostream& operator<<(ostream& os, pair<T, V> x) {
  return os << "( " << x.first << ", " << x.second << " )";
}
template <typename T>
istream& operator>>(istream& is, vector<T>& v) {
  for (auto& e : v) is >> e;
  return is;
}
template <typename T, typename V>
istream& operator>>(istream& is, pair<T, V>& x) {
  return is >> x.first >> x.second;
}
void solve();
int main() { solve(); }
void solve() {
  int n;
  cin >> n;
  vector<ii> A, B;
  for (int i = 1; i <= n; ++i) {
    int a, b;
    cin >> a >> b;
    if (a < b) {
      A.push_back({-a, i});
    } else {
      B.push_back({a, i});
    }
  }
  if (A.size() > B.size()) {
    cout << A.size() << "\n";
    sort(A.begin(), A.end());
    for (auto e : A) cout << e.second << " ";
    cout << "\n";
  } else {
    cout << B.size() << "\n";
    sort(B.begin(), B.end());
    for (auto e : B) cout << e.second << " ";
    cout << "\n";
  }
}
