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
# ANSHUL GAUTAM
# IIIT-D

from math import *
from copy import *
from string import *				# alpha = ascii_lowercase
from random import *
from sys import stdin
from sys import maxsize
from operator import *				# d = sorted(d.items(), key=itemgetter(1))
from itertools import *
from collections import Counter		# d = dict(Counter(l))

'''
7
1 1
10 1
100 3
1024 14
998244353 1337
123 144
1234312817382646 13
'''

Q = int(stdin.readline())
for q in range(Q):
	n,m = map(int, stdin.readline().rstrip().split())
	M = deepcopy(m)
	ans,zz = 0,n//m
	if(m == n):
		ans = n%10
	elif(m > n):
		ans = 0
	else:
		l = [0]*10
		for i in range(10):
			l[i] = m%10
			m += M
		z = zz//10
		ans += sum(l)*z
		z = zz%10
		ans += sum(l[:z])
	print(ans)
