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A11377. Find Extra One

编程题 普及/提高-

题目描述

You have $n$ distinct points on a plane, none of them lie on $OY$ axis. Check that there is a point after removal of which the remaining points are located on one side of the $OY$ axis.

输入格式

The first line contains a single positive integer $n$ ( $2<=n<=10^{5}$ ).

The following $n$ lines contain coordinates of the points. The $i$ -th of these lines contains two single integers $x_{i}$ and $y_{i}$ ( $|x_{i}|,|y_{i}|<=10^{9}$ , $x_{i}≠0$ ). No two points coincide.

输出格式

Print "Yes" if there is such a point, "No" — otherwise.

You can print every letter in any case (upper or lower).

输入输出样例

输入 #1
3
1 1
-1 -1
2 -1
输出 #1
Yes
输入 #2
4
1 1
2 2
-1 1
-2 2
输出 #2
No
输入 #3
3
1 2
2 1
4 60
输出 #3
Yes

说明/提示

In the first example the second point can be removed.

In the second example there is no suitable for the condition point.

In the third example any point can be removed.
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