CF900A.Find Extra One

普及/提高-

通过率:0%

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题目描述

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

输入格式

The first line contains a single positive integer nn ( 2<=n<=1052<=n<=10^{5} ).

The following nn lines contain coordinates of the points. The ii -th of these lines contains two single integers xix_{i} and yiy_{i} ( xi,yi<=109|x_{i}|,|y_{i}|<=10^{9} , xi0x_{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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