900AFind Extra One

A. Find Extra One

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

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.

Input

The first line contains a single positive integer n (2 ≤ n ≤ 105).

The following n lines contain coordinates of the points. The i-th of these lines contains two single integers xi and yi (|xi|, |yi| ≤ 109, xi ≠ 0). No two points coincide.

Output

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

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

Examples

input

31 1-1 -12 -1

output

Yes

input

41 12 2-1 1-2 2

output

No

input

31 22 14 60

output

Yes

Note

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.

题意:在坐标系中，给你n个点的坐标，让你去掉一个点，如果这些点能够在y轴同一侧，就输出Yes,否则就输出No。

题解：主要判断横坐标>0和小于0的个数。如果两个个数

#include<bits/stdc++.h>using namespace std;int main(){    int n,cnt1,cnt2,x,y;    while(cin>>n)    {        cnt1=cnt2=0;        for(int i=0; i<n; i++)        {            cin>>x>>y;            if(x>0)                cnt1++;            else cnt2++;        }        if(cnt1>1&&cnt2>1)            puts("No");        else            puts("Yes");    }    return 0;}

都大于1，肯定不行的，其余情况就输出是可以的。