#include <bits/stdc++.h>
using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define DEBUG(...)
#endif

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  vector v(500, vector(500, -1));
  auto f = [&](int ox, int oy, int id) {
    for (int y = oy; y < 500; y += 9) {
      for (int x = (ox + 5 * ((y ^ oy) & 1)) % 10; x < 500; x += 10) {
        v[x][y] = id;
      }
    }
  };
  int id = 0;
  for (int x = 0; x < 10; ++x) {
    for (int y = 0; y < 9; ++y) {
      f(x, y, id++);
    }
  }
  int n;
  cin >> n;
  vector<int> x(n), y(n), cnt(90);
  for (int i = 0; i < n; ++i) {
    cin >> x[i] >> y[i];
    --x[i], --y[i];
    ++cnt[v[x[i]][y[i]]];
  }
  int mi = max_element(begin(cnt), end(cnt)) - begin(cnt);
  vector<int> res;
  for (int i = 0; i < n; ++i) {
    if (v[x[i]][y[i]] == mi) {
      res.push_back(i);
    }
  }
  int k = size(res);
  cout << k << '\n';
  for (int i = 0; i < k; ++i) {
    cout << res[i] + 1 << " \n"[i == k - 1];
  }
}