B'You are given two strings a and b of length n . Then, you are (forced against your will) to answer q queries. For each query, you are given a range bounded by l and r . In one operation, you can choose an integer i ( l <= q i <= q r ) and set a_i = x where x is any character you desire. Output the minimum number of operations you must perform such that texttt{sorted(a[l..r])} = texttt{sorted(b[l..r])} . The operations you perform on one query does not affect other queries. For an arbitrary string c , texttt{sorted(c[l..r])} denotes the substring consisting of characters c_l, c_{l+1}, ... , c_r sorted in lexicographical order. The first line contains t ( 1 <= q t <= q 1000 ) xe2 x80 x93 the number of test cases. The first line of each test case contains two integers n and q ( 1 <= q n, q <= q 2 cdot 10^5 ) xe2 x80 x93 the length of both strings and the number of queries. The following line contains a of length n . It is guaranteed a only contains lowercase latin letters. The following line contains b of length n . It is guaranteed b only contains lowercase latin letters. The following q lines contain two integers l and r ( 1 <= q l <= q r <= q n ) xe2 x80 x93 the range of the query. It is guaranteed the sum of n and q over all test cases does not exceed 2 cdot 10^5 . For each query, output an integer, the minimum number of operations you need to perform in a new line. For the first query, texttt{sorted(a[1..5])} = abcde and texttt{sorted(b[1..5])} = abcde, so no operations are necessary. For the second query, you need to set a_1 = e. Then, texttt{sorted(a[1..4])} = texttt{sorted(b[1..4])} = bcde. '...