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
for _ in range(int(input())):
	n, m = map(int, input().split())
	if n < m:
		print(0)
		continue
	if n == m:
		print(n%10)
		continue
	# m = m%10;
	a = []
	b = []
	for i in range(1,11):
		if i*m > n:
			break
		a.append((i*m)%10)
		b.append(i*m)
	
	su = sum(a)
	# print(su)
	nq = n//(b[len(b)-1])
	su = su*nq
	s = n-(nq*b[len(b)-1])
	# print(su, s, b, a, nq)
	for i in range(len(b)):
		if b[i] <= s:
			su+=(b[i]%10)
	print(su)