B"You are given a set S , which contains the first n positive integers: 1, 2, ldots, n . You can perform the following operation on S any number of times (possibly zero): You are given a set T , which is a subset of S . Find the minimum possible total cost of operations such that S would be transformed into T . We can show that such a transformation is always possible. The first line of the input contains a single integer t ( 1 <= t <= 10 ,000 ) -- the number of test cases. The description of the test cases follows. The first line contains a single positive integer n ( 1 <= n <= 10^6 ). The second line of each test case contains a binary string of length n , describing the set T . The i -th character of the string is '1' if and only if i is an element of T , and '0' otherwise. It is guaranteed that the sum of n over all test cases does not exceed 10^6 . For each test case, output one non-negative integer -- the minimum possible total cost of operations such that S would be transformed into T . In the first test case, we shall not perform any operations as S is already equal to T , which is the set {1, 2, 3, 4, 5, 6 } . In the second test case, initially, S = {1, 2, 3, 4, 5, 6, 7 } , and T = {1, 2, 4, 7 } . We shall perform the following operations: The total cost is 3+3+5 = 11 . It can be shown that this is the smallest cost possible. In the third test case, initially, S = {1, 2, 3, 4 } and T = { } (empty set). We shall perform 4 operations of k=1 to delete 1 , 2 , 3 , and 4 . In the fourth test case, initially, S = {1, 2, 3, 4 } and T = {3 } . We shall perform two operations with k=1 to delete 1 and 2 , then perform one operation with k=2 to delete 4 . "...