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

'''
import sys
from collections import defaultdict as dd
from itertools import  permutations as pp
from itertools import combinations as cc
from collections import Counter as ccd
from random import randint as rd
from bisect import bisect_left as bl
from  heapq import heappush as hpush
from heapq import heappop as hpop
mod=10**9+7

def ri(flag=0):
	if flag==0:
		return [int(i) for i in sys.stdin.readline().split()]
	else:
		return int(sys.stdin.readline())


for _ in range(ri(1)):
	n,m= ri()
	k = []
	for i in range(m,n+1,m):
		temp = i%10
		if temp not in k:
			k.append(temp)
		else:
			break
	
	period = n//m
	ans =0
	if len(k)!=0:
		ans = sum(k)*(period//len(k))
		rem = period %len(k)

		for i in range(rem):
			ans += k[i]

	print(ans)
	#print(k,period)