B"You are given two strings x and y , both consist only of lowercase Latin letters. Let |s| be the length of string s . Let's call a sequence a a merging sequence if it consists of exactly |x| zeros and exactly |y| ones in some order. A merge z is produced from a sequence a by the following rules: Two merging sequences a and b are different if there is some position i such that a_i neq b_i . Let's call a string z chaotic if for all i from 2 to |z| z_{i-1} neq z_i . Let s[l,r] for some 1 <= l <= r <= |s| be a substring of consecutive letters of s , starting from position l and ending at position r inclusive. Let f(l_1, r_1, l_2, r_2) be the number of different merging sequences of x[l_1,r_1] and y[l_2,r_2] that produce chaotic merges. Note that only non-empty substrings of x and y are considered. Calculate sum limits_{1 <= l_1 <= r_1 <= |x| 1 <= l_2 <= r_2 <= |y|} f(l_1, r_1, l_2, r_2) . Output the answer modulo 998 ,244 ,353 . The first line contains a string x ( 1 <= |x| <= 1000 ). The second line contains a string y ( 1 <= |y| <= 1000 ). Both strings consist only of lowercase Latin letters. Print a single integer -- the sum of f(l_1, r_1, l_2, r_2) over 1 <= l_1 <= r_1 <= |x| and 1 <= l_2 <= r_2 <= |y| modulo 998 ,244 ,353 . In the first example there are: Thus, the answer is 6 cdot 2 + 3 cdot 1 + 4 cdot 1 + 2 cdot 2 + 2 cdot 0 + 1 cdot 1 = 24 . "...