B'You are given an array a consisting of n integers. You have to perform the sequence of n-2 operations on this array: So, during the i -th operation, you add the value of a_{i+1} to one of its neighbors, and subtract it from the other neighbor. For example, if you have the array [1, 2, 3, 4, 5] , one of the possible sequences of operations is: So, the resulting array is [3, 1, -4, 5, 10] . An array is reachable if it can be obtained by performing the aforementioned sequence of operations on a . You have to calculate the number of reachable arrays, and print it modulo 998244353 . The first line contains one integer n ( 3 <= n <= 300 ). The second line contains n integers a_1, a_2, ... , a_n ( 0 <= a_i <= 300 ). Print one integer -- the number of reachable arrays. Since the answer can be very large, print its remainder modulo 998244353 . '...