#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline int Chkmax(T &a, T b) {
  return a < b ? a = b, 1 : 0;
}
template <typename T>
inline int Chkmin(T &a, T b) {
  return a > b ? a = b, 1 : 0;
}
template <typename T>
inline T read() {
  T sum = 0, fl = 1;
  char ch = getchar();
  for (; !isdigit(ch); ch = getchar())
    if (ch == '-') fl = -1;
  for (; isdigit(ch); ch = getchar()) sum = (sum << 3) + (sum << 1) + ch - '0';
  return sum * fl;
}
inline void proc_status() {
  ifstream t("/proc/self/status");
  cerr << string(istreambuf_iterator<char>(t), istreambuf_iterator<char>())
       << endl;
}
const int Maxn = 1e6 + 100;
int N, Ra[Maxn], Rb[Maxn];
int Rank[Maxn];
vector<pair<pair<int, int>, int> > A, B;
inline int cmp1(int a, int b) { return A[a].first.second > A[b].first.second; }
inline int cmp2(int a, int b) { return B[a].first.first < B[b].first.first; }
inline void Solve() {
  int cnt0 = 0, cnt1 = 0;
  for (int i = 1; i <= N; ++i) {
    if (Ra[i] < Rb[i])
      A.push_back(make_pair(make_pair(Ra[i], Rb[i]), i));
    else
      B.push_back(make_pair(make_pair(Ra[i], Rb[i]), i));
  }
  for (int i = 0; i < N; ++i) Rank[i] = i;
  if (A.size() >= B.size()) {
    int n = A.size();
    cout << n << endl;
    sort(Rank, Rank + n, cmp1);
    for (int i = 0; i < n; ++i) cout << A[Rank[i]].second << ' ';
  } else {
    int n = B.size();
    cout << n << endl;
    sort(Rank, Rank + n, cmp2);
    for (int i = 0; i < n; ++i) cout << B[Rank[i]].second << ' ';
  }
}
inline void Input() {
  N = read<int>();
  for (int i = 1; i <= N; ++i) Ra[i] = read<int>(), Rb[i] = read<int>();
}
int main() {
  Input();
  Solve();
  return 0;
}
