B'You are given an integer n and three strings a, b, c , each consisting of n lowercase Latin letters. Let a template be a string t consisting of n lowercase and/or uppercase Latin letters. The string s matches the template t if the following conditions hold for all i from 1 to n : Accordingly, the string doesn 't match the template if the condition doesn 't hold for at least one i . Determine whether there exists a template t such that the strings a and b match it, while the string c does not. The first line contains an integer t ( 1 <= t <= 1000 ) -- the number of test cases. The first line of each test case contains an integer n ( 1 <= n <= 20 ) -- the length of the given strings. The next three lines contain the strings a, b and c . Each string consists of exactly n lowercase Latin letters. For each testcase, print "YES" if there exists a template t such that the strings a and b match it, while the string c does not. Otherwise, print "NO". In the first test case, you can use the template "C". The first letter of strings a and b differ from 'c ', so they match the template. The first letter of string c equals 'c ', so it doesn 't match. In the third test case, you can use the template "CODEforces". '...