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
from sys import stdin, stdout

T = int(stdin.readline().rstrip())

for t in range(T):
	n, m = [int(x) for x in stdin.readline().rstrip().split()]
	if (n > m):
		l = []
		i = m
		while (True):
			x = str(i)
			y = int(x[len(x) - 1])
			if (y in l):
				break
			else:
				l.append(y)
			i += m
		ans = 0
		i -= m
		if (n <= i):
			j = m
			for k in range(len(l)):
				if (j <= n):
					j += m
					ans += l[k]
				else:
					break
		else:
			ans += (n // i) * sum(l)
			k = n - (n // i) * i
			if (k >= m):
				ans += sum(l[0 : (k // m)])
		stdout.write(str(ans) + '\n')
	elif (n < m):
		stdout.write("0\n")
	else:
		x = str(m)
		stdout.write(str(x[len(x) - 1]) + '\n')
			  		 	 	 		 	    		   	    	