A group of Czech tourists is walking in a labyrinth of a strange self-similar shape. The ground plan of the labyrinth is a Sierpinski triangle - a fractal structure named after the Polish mathematician Waclaw Sierpiski.

The labyrinth consists of a billion rows numbered from 0 to 10^9-1 from top to bottom, and a billion columns numbered from 0 to 10^9 - 1 from left to right. The fields in the labyrinth can be either free or blocked. The field in row X and column Y is free if the result of the bitwise ‘and’ operation on the numbers X and Y is equal to zero, otherwise it is blocked. In other words, a field is blocked if, when X and Y are switched to binary, there is an integer k such that the k-th digit from the right of the number X and the k-th digit from the right of the number Y are equal to 1.

The Czech tourists are tired from a long day of wandering and would like to meet up in a free field and exchange experiences. In each step, one tourist can jump to one of the adjacent free fields (up, down, left or right).

Write a programme that will, based on the current tourists’ locations, determine minimum total number of steps necessary in order for all the tourists to meet in the same field.

입력

• The first line of input contains an integer N - the number of tourists.
• Each of the following N lines contains two integers Ri and Si - the row and column of the field where the i-th tourist is located. All the tourists are located in free fields, and it is possible that there are multiple tourists in the same field.

출력

Please note: We recommend that you use a 64-bit integer data type (int64 in Pascal, long long in C/C++).

입출력 예

입력

2
2 1
4 3

출력

6 

입력

6
2 5
3 4
8 7
9 6
10 5
11 4

출력

50

Clarification of the first example: One of the fields where the brave Czech tourists could have met is
(2, 0).

Clarification of the second example: One of the fields where the playful Czech tourists could have met
is (8, 4).

출처:2013-2014 olympiad 1/4