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

lnums = [[1, 2, 3, 4, 5, 6, 7, 8, 9, 0],
         [2, 4, 6, 8, 0, 2, 4, 6, 8, 0],
         [3, 6, 9, 2, 5, 8, 1, 4, 7, 0],
         [4, 8, 2, 6, 0, 4, 8, 2, 6, 0],
         [5, 0, 5, 0, 5, 0, 5, 0, 5, 0],
         [6, 2, 8, 4, 0, 6, 2, 8, 4, 0],
         [7, 4, 1, 8, 5, 2, 9, 6, 3, 0],
         [8, 6, 4, 2, 0, 8, 6, 4, 2, 0],
         [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]]


def solve(ninput, lnums):
    total_sum = 0
    n, m = int(ninput[0]), int(ninput[1])
    last_digit = int(ninput[1][-1]) - 1
    if last_digit == -1 or m > n:
        return total_sum
    repeat = n // m
    quotient, rem = divmod(repeat, 10)
    total_sum += (quotient * sum(lnums[last_digit]))
    total_sum += sum(lnums[last_digit][:rem])
    return total_sum


n = int(input())

for _ in range(n):
    ninput = input().split()
    print(solve(ninput, lnums))

	  					   	     				    	 	  	