B"You are given n segments on the coordinate axis. The i -th segment is [l_i, r_i] . Let's denote the set of all integer points belonging to the i -th segment as S_i . Let A cup B be the union of two sets A and B , A cap B be the intersection of two sets A and B , and A oplus B be the symmetric difference of A and B (a set which contains all elements of A and all elements of B , except for the ones that belong to both sets). Let [ mathbin{op}_1, mathbin{op}_2, ... , mathbin{op}_{n-1}] be an array where each element is either cup , oplus , or cap . Over all 3^{n-1} ways to choose this array, calculate the sum of the following values: |(((S_1 mathbin{op}_1 S_2) mathbin{op}_2 S_3) mathbin{op}_3 S_4) ... mathbin{op}_{n-1} S_n| In this expression, |S| denotes the size of the set S . The first line contains one integer n ( 2 <= n <= 3 cdot 10^5 ). Then, n lines follow. The i -th of them contains two integers l_i and r_i ( 0 <= l_i <= r_i <= 3 cdot 10^5 ). Print one integer -- the sum of |(((S_1 mathbin{op}_1 S_2) mathbin{op}_2 S_3) mathbin{op}_3 S_4) ... mathbin{op}_{n-1} S_n| over all possible ways to choose [ mathbin{op}_1, mathbin{op}_2, ... , mathbin{op}_{n-1}] . Since the answer can be huge, print it modulo 998244353 . "...