Bar Arrangement

There are $n$ bars of heights $1, 2, \dots, n$ placed in a row. When you look at the bars from the left or from the right, a taller bar hides any shorter bar behind it. Consider the two arrangements of $4$ bars shown below.

In both arrangements, exactly $1$ bar is visible from the left and exactly $2$ bars are visible from the right.

Given the number of bars $n$, the number of bars $l$ visible from the left, and the number of bars $r$ visible from the right, write a program that counts how many arrangements produce this result.

The first line contains the number of test cases $T$. Each test case consists of a single line with three integers $n$, $l$, and $r$. ($1 \le l, r \le n \le 20$)

For each test case, print the number of arrangements corresponding to the given $n$, $l$, and $r$, one per line.