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
import math
def BookReading(l):
    n_ = l[0]
    m_ = l[1]
    
    sum_ = 0
    curr_n = 0
    multiples = 0
    i=1
    while(1):
        multiples += m_ 
        sum_ += multiples%10
        curr_n = multiples%10
        if curr_n==0:
            break
        i+=1
    without_r = sum_*math.floor((n_/m_)/i)
    r= n_//m_%i
    # print(r,i,sum_)
    sum_ = 0
    multiples = 0
    for j in range(0,r):
        multiples += m_ 
        sum_ += multiples%10
        # print(multiples,sum_)
    with_r = sum_
    if r==0: with_r=0
    # print(with_r)
    print(without_r+with_r)
    
    
n = int(input())
for i in range(0,n):
    BookReading(list(map(int, input().rstrip().split())))