Last Digit Sum

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For a nonnegative 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 nonnegative 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.
Sample Input
3 1 8 28 138 314159 314159
Sample Output
36 495 7
Constraints
 T ≤ 1000
 0 ≤ A ≤ B ≤ 400,000,000
Author:  pieguy 
Tester:  chmel_tolstiy 
Editorial  http://discuss.codechef.com/problems/LASTDIG 
Tags  cook14, easy, pieguy 
Date Added:  2092011 
Time Limit:  0.30303 sec 
Source Limit:  50000 Bytes 
Languages:  C, CPP14, JAVA, PYTH, PYTH 3.6, CS2, PAS fpc, PAS gpc, RUBY, PHP, GO, NODEJS, HASK, SCALA, D, PERL, FORT, WSPC, ADA, CAML, ICK, BF, ASM, CLPS, PRLG, ICON, SCM qobi, PIKE, ST, NICE, LUA, BASH, NEM, LISP sbcl, LISP clisp, SCM guile, JS, ERL, TCL, PERL6, TEXT, PYP3, CLOJ, FS 
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