B"You are given two integers l and r , where l < r . We will add 1 to l until the result is equal to r . Thus, there will be exactly r-l additions performed. For each such addition, let's look at the number of digits that will be changed after it. For example: Changed digits always form a suffix of the result written in the decimal system. Output the total number of changed digits, if you want to get r from l , adding 1 each time. The first line contains an integer t ( 1 <= t <= 10^4 ). Then t test cases follow. Each test case is characterized by two integers l and r ( 1 <= l < r <= 10^9 ). For each test case, calculate the total number of changed digits if you want to get r from l , adding one each time. "...