문제2692--Pole Arrangement

### 2692: Pole Arrangement

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#### 문제 설명

There are n poles of height 1, 2, ... , n in a row. If you look at these poles from the left side or the right side, smaller poles are hidden by taller poles. For example, consider the two arrangements of 4 poles in the next figure:

For each arrangement, only one pole can be seen from the left, and two poles can be seen from the right.

You are to write a program to calculate the number of arrangements of n poles such that seen from the left you see l poles and seen from the right you see r poles.

#### 입력 설명

Your program is to read from standard input. The input consists of T test cases. The number of test cases T is given in the first line of the input. Each test case consists of a line containing three integers, n, l, and r (1 ≤ l,r ≤ n ≤ 20), where n is the number of poles and (resp. r) is the number of poles that can be seen from the left(resp. right).

#### 출력 설명

Your program is to write to standard output. Print exactly one line for each test case. The line should contain the number of arrangements of poles for the test case.

#### 입력 예시 Copy

4
4 1 2
4 1 1
5 2 4
20 2 1

#### 출력 예시 Copy

2
0
4
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