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C. Points on Plane

原题:http://codeforces.com/problemset/problem/576/C

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:  (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 .

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 .

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:

(|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


题目大意:

给出平面n(n<=1e6)个点的坐标,坐标范围均为[0..1e6]。求构造一个遍历顺序,使得走过的曼哈顿距离不超过2.5e9


个人解法:

直接莫队啊……?

然后设块的大小是1000。

然后交了一发WA。

后来仔细处理了一下块的大小。

然后就过了……

这个题告诉我们1e6不用想莫队了。


代码如下:

http://codeforces.com/contest/576/submission/25969415

 
 
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