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;
const int MAX_N = 1002015;
int n;
pair<pair<int, int>, int> s[MAX_N];
bool cmp2_0(pair<pair<int, int>, int> a, pair<pair<int, int>, int> b) {
  return a.first.second < b.first.second;
}
bool cmp2_1(pair<pair<int, int>, int> a, pair<pair<int, int>, int> b) {
  return a.first.second > b.first.second;
}
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) {
    scanf("%d%d", &s[i].first.first, &s[i].first.second);
    s[i].second = i;
  }
  sort(s, s + n);
  int sqrt_n = int(sqrt(n));
  int j = 0;
  int cnt = 0;
  for (int i = 1000; j < n; i += 1000) {
    cnt = !cnt;
    int op = j;
    while (j < n && s[j].first.first <= i) ++j;
    if (cnt)
      sort(s + op, s + j, cmp2_1);
    else
      sort(s + op, s + j, cmp2_0);
  }
  for (int i = 0; i < n; ++i) {
    printf("%d ", s[i].second + 1);
  }
  puts("");
  return 0;
}
