#include <bits/stdc++.h>
using namespace std;
int main() {
  static int n;
  static int a[300010], b[300010];
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d%d", &a[i], &b[i]);
  int cnt[2] = {};
  for (int i = 1; i <= n; i++) {
    if (a[i] < b[i])
      cnt[0]++;
    else
      cnt[1]++;
  }
  if (cnt[0] > cnt[1]) {
    vector<pair<int, int> > vec;
    for (int i = 1; i <= n; i++) {
      if (a[i] < b[i]) vec.push_back(pair<int, int>(-a[i], i));
    }
    sort(vec.begin(), vec.end());
    printf("%d\n", cnt[0]);
    for (int i = 0; i < vec.size(); i++) {
      printf("%d%c", vec[i].second, (i + 1 == vec.size()) ? '\n' : ' ');
    }
  } else {
    vector<pair<int, int> > vec;
    for (int i = 1; i <= n; i++) {
      if (a[i] > b[i]) vec.push_back(pair<int, int>(b[i], i));
    }
    sort(vec.begin(), vec.end());
    printf("%d\n", cnt[1]);
    for (int i = 0; i < vec.size(); i++) {
      printf("%d%c", vec[i].second, (i + 1 == vec.size()) ? '\n' : ' ');
    }
  }
}
