14341434 SUSTech Online Judge
Problem 1434 --Tidy cables

## 1434: Tidy cables

Time Limit: 1 Sec  Memory Limit: 128 MB
Submit: 118  Solved: 35
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## Description

There are too many cables under your table, and you want to tidy them. You designed a simple cabling scheme: There are $$n$$ cables, each cable is a line in form of $$y = k_i*x + b_i$$, your table is the region between $$x = x_1$$ and $$x = x_2$$. If any two cables intersect on your table region (not include the edges), your table is not tidy and you need to design another scheme.

More formally, there are $$n$$ lines in form of $$y = k_i*x + b_i$$, if there are two lines intersect on $$(x_p, y_p)$$, and $$x_1 < x_p < x_2$$, then the scheme need be redesigned.

You want to know whether you need to redesign the scheme.

## Input

The first line of the input contains an integer $$n$$ $$(2 ≤ n ≤ 10^5)$$

The second line contains two integers $$x_1$$ and $$x_2$$ $$( - 10^9 ≤ x_1 < x_2 ≤ 10^9)$$

The following n lines contain integers $$k_i , b_i$$  $$( -10^6 ≤ k_i , b_i ≤ 10^6)$$, which describe lines. It is guaranteed that all cables are pairwise distinct.

## Output

If you need redesign the scheme, print "YES" (without quotes).

Else, print "NO".

## Sample Input

2
1 3
1 0
-1 3

## Sample Output

YES

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