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
chains = [[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]]

def last_digit(n):
	x = str(n)
	return int(x[-1])

def solve(n,m):
	n_d = n//m
	l_d = last_digit(m)

	ret = (n_d//len(chains[l_d]))*sum(chains[l_d])

	rem = n_d %(len(chains[l_d]))
	
	i = 0
	while rem > 0:
		ret += chains[l_d][i]
		i += 1
		rem -= 1

	return ret

def main():
	t = int(input())

	for _ in range(t):
		n,m = list(map(int, input().strip().split()))

		print (solve(n,m))


if __name__ == "__main__":
	main()
