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
l = []
l.append([])
l.append([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
l.append([0,2, 4, 6, 8])
l.append([0,3,6,9,2,5,8,1,4,7])
l.append([0,4,8,2,6])
l.append([0, 5])
l.append([0,6,2,8,4])
l.append([0, 7, 4, 1, 8, 5, 2, 9, 6, 3])
l.append([0,8, 6, 4, 2])
l.append([0,9,8,7,6,5,4,3,2,1])

q = int(input())
for u in range(q):
    n, m = [int(x) for x in input().split()]

    t = n//m

    last = int(str(m)[-1])

    if last == 0:
        print(0)
    else:
        print(sum(l[last]) * (t//len(l[last])) + sum(l[last][:t%len(l[last])+1]))

	  			 							 							    	 			