CF1795B.Ideal Point

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题目描述

You are given nn one-dimensional segments (each segment is denoted by two integers — its endpoints).

Let's define the function f(x)f(x) as the number of segments covering point xx (a segment covers the point xx if lxrl \le x \le r , where ll is the left endpoint and rr is the right endpoint of the segment).

An integer point xx is called ideal if it belongs to more segments than any other integer point, i. e. f(y)<f(x)f(y) < f(x) is true for any other integer point yy .

You are given an integer kk . Your task is to determine whether it is possible to remove some (possibly zero) segments, so that the given point kk becomes ideal.

输入格式

The first line contains one integer tt ( 1t10001 \le t \le 1000 ) — the number of test cases.

The first line of each test case contains two integers nn and kk ( 1n,k501 \le n, k \le 50 ).

Then nn lines follow, ii -th line of them contains two integers lil_i and rir_i ( 1li,ri501 \le l_i, r_i \le 50 ; liril_i \le r_i ) — the endpoints of the ii -th segment.

输出格式

For each test case, print YES if it is possible to remove some (possibly zero) segments, so that the given point kk becomes ideal, otherwise print NO.

You may print each letter in any case (YES, yes, Yes will all be recognized as positive answer, NO, no and nO will all be recognized as negative answer).

输入输出样例

  • 输入#1

    4
    4 3
    1 3
    7 9
    2 5
    3 6
    2 9
    1 4
    3 7
    1 3
    2 4
    3 5
    1 4
    6 7
    5 5

    输出#1

    YES
    NO
    NO
    YES

说明/提示

In the first example, the point 33 is already ideal (it is covered by three segments), so you don't have to delete anything.

In the fourth example, you can delete everything except the segment [5,5][5, 5] .

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