Polycarp is reading a book consisting of n pages numbered from 1 to n. Every time he finishes the page with the number divisible by m, he writes down the last digit of this page number. For example, if n=15 and m=5, pages divisible by m are 5, 10, 15. Their last digits are 5, 0, 5 correspondingly, their sum is 10.

Your task is to calculate the sum of all digits Polycarp has written down.

You have to answer q independent queries.

Input

The first line of the input contains one integer q (1 ≤ q ≤ 1000) — the number of queries.

The following q lines contain queries, one per line. Each query is given as two integers n and m (1 ≤ n, m ≤ 10^{16}) — the number of pages in the book and required divisor, respectively.

Output

For each query print the answer for it — the sum of digits written down by Polycarp.

Example

Input


7
1 1
10 1
100 3
1024 14
998244353 1337
123 144
1234312817382646 13


Output


1
45
153
294
3359835
0
427262129093995
#double underscore makes a class variable or a class method private
mod = 1000000007
ii = lambda : int(input())
si = lambda : input()
dgl = lambda : list(map(int, input()))
f = lambda : map(int, input().split())
il = lambda : list(map(int, input().split()))
it = lambda : tuple(map(int, input().split()))
ls = lambda : list(input())
l=[[0],[1,2,3,4,5,6,7,8,9,0],[2,4,6,8,0],[3,6,9,2,5,8,1,4,7,0],[4,8,2,6,0],[5,0],[6,2,8,4,0],[7,4,1,8,5,2,9,6,3,0],[8,6,4,2,0],[9,8,7,6,5,4,3,2,1,0]]
t=ii()
for _ in range(t):
    n, m=f()
    nom=n//m
    ldgt=m%10
    num = nom//len(l[ldgt])
    sm = num*sum(l[ldgt])+sum(l[ldgt][i] for i in range(nom % len(l[ldgt])))
    print(sm)
