Solve the programming task below in a Python markdown code block.
For a non-negative integer N, define S(N) as the sum of the odd digits of N
plus twice the sum of the even digits of N.
For example, S(5)=5, S(456)=2*4+5+2*6=25, and S(314159)=3+1+2*4+1+5+9=27.
Define D(N) as the last digit of S(N).
So D(5)=5, D(456)=5, and D(314159)=7.
Given 2 non-negative integers A and B, compute the sum of D(N) over all N between A and B, inclusive.

------ Input ------ 

Input will begin with an integer T, the number of test cases.
T lines follow, each containing 2 integers A and B.

------ Output ------ 

For each test case, output a single integer indicating the corresponding sum.

------ Constraints ------ 

$T ≤ 1000$
$0 ≤ A ≤ B ≤ 400,000,000$

----- Sample Input 1 ------ 
3
1 8
28 138
314159 314159
----- Sample Output 1 ------ 
36
495
7