F. Interesting Functiontime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou 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:   if l=909, then adding one will result in 910 and 2 digits will be changed;  if you add one to l=9, the result will be 10 and 2 digits will also be changed;  if you add one to l=489999, the result will be 490000 and 5 digits will be changed. 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.InputThe first line contains an integer t (1 \le t \le 10^4). Then t test cases follow.Each test case is characterized by two integers l and r (1 \le l < r \le 10^9).OutputFor each test case, calculate the total number of changed digits if you want to get r from l, adding one each time.ExampleInput
4
1 9
9 10
10 20
1 1000000000
Output
8
2
11
1111111110

4
1 9
9 10
10 20
1 1000000000

8 2 11 1111111110 
['binary search', 'dp', 'math', 'number theory', '*1500']