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())
#     s = ""
#     for k in range(n*m):
#     	arr = [0]*(n*m)
#     	x = 0
#     	c = 0
#     	for i in range(n*m):
    		

#     	# arr2 = []
#     	# c = 0
#     	# for i in range(m):
#     	# 	for j in range(n):
#     	# 		if c%(k+1)==0:
#     	# 			if arr[j*n+i]!=1:
#     	# 				x+=1
#     	# 		c+=1
#     	# print(str(k) + " " + str(len(arr1)) + " " + str(len(arr2)))
#     	# s += str(len(arr)) + " "
#     	s+= str(x)+ " "
#     print(s)
#     	
for _ in range(int(input())):
	n,m = map(int,input().split())
	arr = []
	i = 1
	while int(str(m*i)[-1])!=0:
		arr.append(int(str(m*i)[-1]))
		i+=1
	arr.append(0)
	# print(arr)
	s = sum(arr)
	summ = 0
	x = len(arr)*m
	v = n//x
	summ += s*(v)
	y = n-(x*v)
	c = y//m
	summ+=sum(arr[:c])
	print(summ)
