#include <bits/stdc++.h>
using namespace std;
long long n, j, k, a, b;
pair<int, int> c[300005];
map<pair<long long, long long>, long long> m;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a >> b;
    c[i] = make_pair(a, b);
    m[c[i]] = i;
    if (a > b) {
      k++;
    }
  }
  sort(c, c + n);
  j = n - k;
  if (k > j) {
    cout << k << '\n';
    for (int i = 0; i < n; i++) {
      if (c[i].first > c[i].second) {
        cout << m[c[i]] + 1 << " ";
      }
    }
  } else {
    cout << j << '\n';
    for (int i = n - 1; i >= 0; i--) {
      if (c[i].first < c[i].second) {
        cout << m[c[i]] + 1 << " ";
      }
    }
  }
  cout << '\n';
  return 0;
}
