codeforces#P1400G. Mercenaries
Mercenaries
Description
Polycarp plays a (yet another!) strategic computer game. In this game, he leads an army of mercenaries.
Polycarp wants to gather his army for a quest. There are $n$ mercenaries for hire, and the army should consist of some subset of them.
The $i$-th mercenary can be chosen if the resulting number of chosen mercenaries is not less than $l_i$ (otherwise he deems the quest to be doomed) and not greater than $r_i$ (he doesn't want to share the trophies with too many other mercenaries). Furthermore, $m$ pairs of mercenaries hate each other and cannot be chosen for the same quest.
How many non-empty subsets does Polycarp need to consider? In other words, calculate the number of non-empty subsets of mercenaries such that the size of this subset belongs to $[l_i, r_i]$ for each chosen mercenary, and there are no two mercenaries in the subset that hate each other.
The answer may be large, so calculate it modulo $998244353$.
The first line contains two integers $n$ and $m$ ($1 \le n \le 3 \cdot 10^5$, $0 \le m \le \min(20, \dfrac{n(n-1)}{2})$) — the number of mercenaries and the number of pairs of mercenaries that hate each other.
Then $n$ lines follow, the $i$-th of them contains two integers $l_i$ and $r_i$ ($1 \le l_i \le r_i \le n$).
Then $m$ lines follow, the $i$-th of them contains two integers $a_i$ and $b_i$ ($1 \le a_i < b_i \le n$) denoting that the mercenaries $a_i$ and $b_i$ hate each other. There are no two equal pairs in this list.
Print one integer — the number of non-empty subsets meeting the constraints, taken modulo $998244353$.
Input
The first line contains two integers $n$ and $m$ ($1 \le n \le 3 \cdot 10^5$, $0 \le m \le \min(20, \dfrac{n(n-1)}{2})$) — the number of mercenaries and the number of pairs of mercenaries that hate each other.
Then $n$ lines follow, the $i$-th of them contains two integers $l_i$ and $r_i$ ($1 \le l_i \le r_i \le n$).
Then $m$ lines follow, the $i$-th of them contains two integers $a_i$ and $b_i$ ($1 \le a_i < b_i \le n$) denoting that the mercenaries $a_i$ and $b_i$ hate each other. There are no two equal pairs in this list.
Output
Print one integer — the number of non-empty subsets meeting the constraints, taken modulo $998244353$.
Samples
3 0
1 1
2 3
1 3
3
3 1
1 1
2 3
1 3
2 3
2