题目描述

Polycarp is a great fan of television.

He wrote down all the TV programs he is interested in for today. His list contains $n$ shows, $i$ -th of them starts at moment $l_{i}$ and ends at moment $r_{i}$ .

Polycarp owns two TVs. He can watch two different shows simultaneously with two TVs but he can only watch one show at any given moment on a single TV. If one show ends at the same moment some other show starts then you can't watch them on a single TV.

Polycarp wants to check out all $n$ shows. Are two TVs enough to do so?

输入格式

The first line contains one integer $n$ ( $1<=n<=2·10^{5}$ ) — the number of shows.

Each of the next $n$ lines contains two integers $l_{i}$ and $r_{i}$ ( 0<=l_{i}&lt;r_{i}<=10^{9} ) — starting and ending time of $i$ -th show.

输出格式

If Polycarp is able to check out all the shows using only two TVs then print "YES" (without quotes). Otherwise, print "NO" (without quotes).

题目大意

题目描述

Polycarp 很喜欢看电视。

他写下了他今天所有感兴趣的共 $n\,(1 \le n \le 2 \times 10^5)$ 个电视节目。其中第 $i$ 个电视节目在 $l_i$ 时开始， $r_i$ 时结束。 $\,(0 \le l_i, r_i \le 10^9)$

Polycarp 有两个电视。他可以同时在两台电视上看两种不同的节目，但他不能在一台电视上同时看两个不同的节目。如果一个节目结束时另一个节目刚好开始，则他不能在一台电视上看这两个节目。他想看完这 $n$ 个节目，请问两台电视足够吗？

输入格式

第一行一个正整数 $n$ 表示电视节目个数。

接下来 $n$ 行每行两个自然数 $l_i, r_i$，表示第 $i$ 个节目开始和结束的时间。

输出格式

一行一个字符串，如果 Polycarp 能用两台电视看完所有节目，输出 YES，否则输出 NO。```

3
1 2
2 3
4 5

YES

4
1 2
2 3
2 3
1 2

NO