On a plane are n points (xi, yi) with integer coordinates between 0 and 106. The distance between the two points with numbers a and b is said to be the following value: <image> (the distance calculated by such formula is called Manhattan distance).

We call a hamiltonian path to be some permutation pi of numbers from 1 to n. We say that the length of this path is value <image>.

Find some hamiltonian path with a length of no more than 25 × 108. Note that you do not have to minimize the path length.

Input

The first line contains integer n (1 ≤ n ≤ 106).

The i + 1-th line contains the coordinates of the i-th point: xi and yi (0 ≤ xi, yi ≤ 106).

It is guaranteed that no two points coincide.

Output

Print the permutation of numbers pi from 1 to n — the sought Hamiltonian path. The permutation must meet the inequality <image>.

If there are multiple possible answers, print any of them.

It is guaranteed that the answer exists.

Examples

Input

5
0 7
8 10
3 4
5 0
9 12


Output

4 3 1 2 5 

Note

In the sample test the total distance is:

<image>

(|5 - 3| + |0 - 4|) + (|3 - 0| + |4 - 7|) + (|0 - 8| + |7 - 10|) + (|8 - 9| + |10 - 12|) = 2 + 4 + 3 + 3 + 8 + 3 + 1 + 2 = 26
#include <bits/stdc++.h>
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
vector<pair<pair<long long, long long>, long long>> sh;
bool cmp(pair<pair<long long, long long>, long long> x,
         pair<pair<long long, long long>, long long> y) {
  if ((x.first.first / 1000) == (y.first.first / 1000)) {
    if ((x.first.first / 1000) & 1)
      return x.first.second < y.first.second;
    else
      return x.first.second > y.first.second;
  } else
    return (x.first.first / 1000) < (y.first.first / 1000);
}
void solve() {
  long long i, j, k, l, r, m, n, a, b, c, d, x, y, z, t;
  cin >> n;
  for (i = 1; i <= n; i++) {
    cin >> x >> y;
    sh.push_back({{x, y}, i});
  }
  sort(sh.begin(), sh.end(), cmp);
  for (auto &cv : sh) cout << cv.second << ' ';
  cout << endl;
}
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long t = 1;
  while (t--) solve();
  return 0;
}
