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
from collections import Counter
import math
 
def rsingle_int():
    return int(stdin.readline().rstrip())
 
def rmult_int():
    return [ int(x) for x in stdin.readline().rstrip().split() ]
 
def rmult_str():
    return stdin.readline().rstrip().split()
 
def r_str():
    return stdin.readline().rstrip()
    
def rsingle_char():
    return stdin.read(1)

def sortFirst(val):
    return val[0]

def main():
    q = rsingle_int()
    for i in range(q):
        n, m = rmult_int()
        
        m_cnt = n // m
        if m_cnt == 0:
            print(0)
        else:
            sum = m % 10
            period = sum
            cur_cnt = 1
            m_cnt -= 1
            while m_cnt > 0:
                period = (period + m) % 10
                sum += period
                cur_cnt += 1
                m_cnt -= 1
                if period == 0:
                    num_periods = n // (cur_cnt * m) - 1
                    sum += sum * num_periods
                    m_cnt -= num_periods * cur_cnt
                    cur_cnt = 0
                
            print(sum)


main()