B"You are given a binary string s (a binary string is a string consisting of characters 0 and/or 1). Let's call a binary string balanced if the number of subsequences 01 (the number of indices i and j such that 1 <= i < j <= n , s_i=0 and s_j=1 ) equals to the number of subsequences 10 (the number of indices k and l such that 1 <= k < l <= n , s_k=1 and s_l=0 ) in it. For example, the string 1000110 is balanced, because both the number of subsequences 01 and the number of subsequences 10 are equal to 6 . On the other hand, 11010 is not balanced, because the number of subsequences 01 is 1 , but the number of subsequences 10 is 5 . You can perform the following operation any number of times: choose two characters in s and swap them. Your task is to calculate the minimum number of operations to make the string s balanced. The only line contains the string s ( 3 <= |s| <= 100 ) consisting of characters 0 and/or 1. Additional constraint on the input: the string s can be made balanced. Print a single integer -- the minimum number of swap operations to make the string s balanced. In the first example, the string is already balanced, the number of both 01 and 10 is equal to 1 . In the second example, the string is already balanced, the number of both 01 and 10 is equal to 6 . In the third example, one of the possible answers is the following one: 11010 rightarrow 01110. After that, the number of both 01 and 10 is equal to 3 . In the fourth example, one of the possible answers is the following one: 11001100 rightarrow 11001010 rightarrow 11000011. After that, the number of both 01 and 10 is equal to 8 . "...