#include <bits/stdc++.h>
using namespace std;
char ch;
bool f;
inline void read(int &a) {
  f = 1;
  for (ch = getchar(); ch > '9' || ch < '0'; ch = getchar())
    if (ch == '-') f = 0;
  for (a = 0; ch <= '9' && ch >= '0'; ch = getchar()) (a *= 10) += ch - '0';
  if (!f) a = -a;
}
int n, Threshold, maxx, maxy;
struct inf {
  int x, y, p;
} P[1000100];
inline bool Acmp(const inf &a, const inf &b) {
  return a.x / Threshold != b.x / Threshold ? a.x < b.x : a.y < b.y;
}
int main() {
  int i;
  read(n);
  for (i = 1; i <= n; i++) {
    read(P[i].x);
    read(P[i].y);
    P[i].p = i;
    maxx = max(P[i].x, maxx);
    maxy = max(P[i].y, maxy);
  }
  Threshold = ceil(sqrt((long double)maxx * maxy * 2 / n));
  sort(P + 1, P + n + 1, Acmp);
  for (i = 1; i <= n; i++) printf("%d\n", P[i].p);
}

### Prompt

In CPP, your task is to solve the following problem:

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

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
char ch;
bool f;
inline void read(int &a) {
  f = 1;
  for (ch = getchar(); ch > '9' || ch < '0'; ch = getchar())
    if (ch == '-') f = 0;
  for (a = 0; ch <= '9' && ch >= '0'; ch = getchar()) (a *= 10) += ch - '0';
  if (!f) a = -a;
}
int n, Threshold, maxx, maxy;
struct inf {
  int x, y, p;
} P[1000100];
inline bool Acmp(const inf &a, const inf &b) {
  return a.x / Threshold != b.x / Threshold ? a.x < b.x : a.y < b.y;
}
int main() {
  int i;
  read(n);
  for (i = 1; i <= n; i++) {
    read(P[i].x);
    read(P[i].y);
    P[i].p = i;
    maxx = max(P[i].x, maxx);
    maxy = max(P[i].y, maxy);
  }
  Threshold = ceil(sqrt((long double)maxx * maxy * 2 / n));
  sort(P + 1, P + n + 1, Acmp);
  for (i = 1; i <= n; i++) printf("%d\n", P[i].p);
}

```