CF475F Meta-universe

Description

Consider infinite grid of unit cells. Some of those cells are planets. Meta-universe $ M={p_{1},p_{2},...,p_{k}} $ is a set of planets. Suppose there is an infinite row or column with following two properties: 1) it doesn't contain any planet $ p_{i} $ of meta-universe $ M $ on it; 2) there are planets of $ M $ located on both sides from this row or column. In this case we can turn the meta-universe $ M $ into two non-empty meta-universes $ M_{1} $ and $ M_{2} $ containing planets that are located on respective sides of this row or column. A meta-universe which can't be split using operation above is called a universe. We perform such operations until all meta-universes turn to universes. Given positions of the planets in the original meta-universe, find the number of universes that are result of described process. It can be proved that each universe is uniquely identified not depending from order of splitting.

Input Format

Consider infinite grid of unit cells. Some of those cells are planets. Meta-universe $ M={p_{1},p_{2},...,p_{k}} $ is a set of planets. Suppose there is an infinite row or column with following two properties: 1) it doesn't contain any planet $ p_{i} $ of meta-universe $ M $ on it; 2) there are planets of $ M $ located on both sides from this row or column. In this case we can turn the meta-universe $ M $ into two non-empty meta-universes $ M_{1} $ and $ M_{2} $ containing planets that are located on respective sides of this row or column. A meta-universe which can't be split using operation above is called a universe. We perform such operations until all meta-universes turn to universes. Given positions of the planets in the original meta-universe, find the number of universes that are result of described process. It can be proved that each universe is uniquely identified not depending from order of splitting.

Output Format

Print the number of resulting universes.

Explanation/Hint

The following figure describes the first test case: ![](https://cdn.luogu.com.cn/upload/vjudge_pic/CF475F/09f25b4712b12f413b4de2f1fe0b272e040d2345.png)