# ДОРЕШИВАНИЕ 2014 ACM-ICPC Украина, 2ой Раунд Украина, Сентябрь 13

# Fence

Emos have relocated to newly built houses and decided to build a fence around their settlement. Emos are strange people, and they will cry if at least one section of the fence is not parallel to coordinate axis. Therefore, you have a task – to build a fence of minimal length around Emo's settlement in a way that all houses are located inside the area limited by the fence. The fence should be a polygon without self-intersections and self-tangencies with sides parallel to coordinate axis. Houses are points having coordinates. Some houses are allowed to be located at the fence itself.

** Input**

The first line contains integer **n** (**2** ≤ **n** ≤ **100 000**) – number of houses. The following **n** lines contain descriptions of houses – each line contains two integers **x _{i}**,

**y**(

_{i}**-10**≤

^{9}**x**,

_{i}**y**≤

_{i}**10**). All houses are located at different points, at least two

^{9}**x**-coordinates and

**y**-coordinates are different.

** Output**

You need to print one integer – the minimal possible length of the fence.

4 1 0 0 1 1 1 0 0

4