You have just learned the algorithm bubble sort, which is able to sort an array in non-descending order. Let's define the function $\text{sort}(a)$ as in the following pseudocode:
function sort(array a):
rounds := 0
n := length of a
while a is not non-decreasing:
rounds := rounds + 1
for i from 1 to n - 1:
if a[i] > a[i + 1]:
swap(a[i], a[i + 1])
return rounds
As it is shown, the return value of $\text{sort}(a)$ represents the number of rounds needed to make array $a$ sorted in non-descending order by using bubble sort.
You are given an integer $n$, as well as $m$ integer tuples $(k_i,l_i,r_i)$ ($1\le i\le m$). Count the number of permutations$^{\text{∗}}$ $p$ of length $n$, modulo $998\,244\,353$, so that the following restrictions are satisfied:
- For each
$1\le i\le n$, let$b_i=\text{sort}([p_1,p_2,\ldots,p_{i}])$, then - For each
$1\le j\le m$, let$x$be the number of indices$y$($1\le y\le n$) such that$b_y\le k_j$, then$l_j\le x\le r_j$holds.
$^{\text{∗}}$A permutation of length $n$ is an array consisting of $n$ distinct integers from $1$ to $n$ in arbitrary order. For example, $[2,3,1,5,4]$ is a permutation, but $[1,2,2]$ is not a permutation ($2$ appears twice in the array), and $[1,3,4]$ is also not a permutation ($n=3$ but there is $4$ in the array).
Input
Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 10^4$). The description of the test cases follows.
The first line of each test case contains two integers $n$ and $m$ ($2\leq n\leq 10^6$, $0\leq m\leq 1000$).
Then $m$ lines follow, the $i$-th line containing three integers $k_i$, $l_i$, and $r_i$ ($0\le k_i\le n - 1$, $1\le l_i\le r_i\le n$) — the restrictions.
It is guaranteed that the sum of $m^2$ over all test cases does not exceed $10^6$.
Output
For each test case, output a single integer — the number of possible permutations, modulo $998\,244\,353$.
Note
In the first test case, only permutations $[3,1,4,2]$ and $[4,1,3,2]$ satisfy the restrictions. Take $[3,1,4,2]$ as an example. Let's calculate the array $b$:
$\text{sort}([3])=0$;$\text{sort}([3,1])=1$;$\text{sort}([3,1,4])=1$;$\text{sort}([3,1,4,2])=2$.
Thus, $b=[0,1,1,2]$. It is easy to show that it satisfies all the restrictions.
In the second test case, only permutation $[1,2,3]$ satisfies the restrictions.
In the third test case, the following $8$ permutations satisfy the restrictions:
$[2,3,1,4]$;$[2,4,1,3]$;$[3,2,1,4]$;$[3,4,1,2]$;$[3,4,2,1]$;$[4,2,1,3]$;$[4,3,1,2]$;$[4,3,2,1]$.
样例
6
4 3
0 1 1
1 3 3
2 4 4
3 2
0 3 3
1 2 3
4 3
1 2 2
2 3 4
0 1 2
5 3
1 1 4
3 5 5
4 5 5
10 5
1 2 3
2 3 4
3 4 5
4 5 6
5 6 7
1000000 0
2
1
8
80
192600
373341033
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